EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: electromateria on November 09, 2020, 05:01:02 am
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Why can't I get any sweet and succulent 3 phase energy wired directly to my house?
The government and corporations are trying to hog all the 3 phase badassery to themselves. Sickening. We need to protest and fight back against this injustice.
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20 years ago I used to wish I had 3 phase, but now I don't care. When I want to run a 3 phase motor I run it on a VFD, and I'd do the same even if I had 3 phase into the house just due to all the other features it gives you. I have no other use for 3 phase power.
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No worries getting a 3 phase domestic connection in anything but remote areas in NZ except for the cost. ::)
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Why can't I get any sweet and succulent 3 phase energy wired directly to my house?
The government and corporations are trying to hog all the 3 phase badassery to themselves. Sickening. We need to protest and fight back against this injustice.
You almost certainly could, you just might not like the eye-popping, mind-bendingly high price for installation. It really usually depends on how physically close a 7200v supply with all three phases is to your location.
In my case, all three phases are available on the second-closest pole to my house, only one house away on the utility right-of-way, so I would just essentially have to pay for the installation of the three transformers and the wiring to the actual house, but that would likely still be a 5-figure dollar amount, and is simply totally unnecessary for anything I do here. :)
Why do you needwant three phase?
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Well in most of Europe most houses have 3 phase because that is what typically runs down the street on power poles.
If you have single phase then you get bigger main fuses to get the same amount of power out of it, while not having to worry about balancing the load between phases to avoid overloading one of them since there is just one. If you need to run a 3 phase motor, just get a VFD, they are cheap these days.
What is sickening is when an power hungry appliance does not make use of 3 phase and insists on sucking it all out of a single phase. Like for example the heat pump we have heating the house consumes 5kW from a single phase because the VFD inside(for running the 3 phase compressor at various speeds) is only single phase input because PFC is cheaper to do on a single phase. Combined with all the other existing loads in the house this put a lot of strain on that phase, but it was fine since main fuses are not very precise, but then they came up with fancy new smart meters that include a disconnect inside that also trips when phase currents are exceeded in order to protect the main fuses. This smart meter is a lot more precise and so it did trip. Moving some loads to a different phase helped some but it still happened occasionally so we had to pay up to get bigger main fuses.
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If you have single phase then you get bigger main fuses to get the same amount of power out of it, while not having to worry about balancing the load between phases to avoid overloading one of them since there is just one.
Bit different here in NZ where any typical connection is 60A, single or 3 phase however business/industrial connections can be several 100A/phase.
Some decades ago our powerco offered a downrated 3 phase option of 20A/phase where line charges (a component of your bill) remained very similar to a single phase connection however you have the benefit of being able to use 3ph equipment. This provided a significant cost saving compared to the standard 3ph 60A supply and so much so the popularity of this offering meant it didn't last long before it was pulled. :(
We still have an 'existing use' connection of this type to farm buildings where we have all manner of 3ph equipment although we can't use much of it together without tripping the MCB despite they have all been uprated to D curve motor rated MCB's.
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Mine has 3 phase 380V service.
Yes we discovered this after buying a Chinese made 3ph pump after it draws a bit more than labelled current on our 415VAC 3ph. ::)
They sell these here in NZ thinking they're a direct replacement and suitable for the bit higher voltage here.
Still wondering how long it will last.................
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Well in most of Europe most houses have 3 phase because that is what typically runs down the street on power poles.
Here in the UK you can upgrade to 3 phase and get a 70kVA supply. It typically costs a few £k:
https://www.ukpowernetworks.co.uk/electricity/upgrade-reduce-electricity (https://www.ukpowernetworks.co.uk/electricity/upgrade-reduce-electricity)
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Usually 3 phase is delivered to a substation that splits the single phases to different streets. It does not make economic sense to put all 3 phases down every street just in case one person wants it as it adds to the cabling required. No point in the OP going frantic. You want an industrial power supply? move to an industrial location.
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Usually 3 phase is delivered to a substation that splits the single phases to different streets. It does not make economic sense to put all 3 phases down every street just in case one person wants it as it adds to the cabling required. No point in the OP going frantic. You want an industrial power supply? move to an industrial location.
Distribution methods vary immensely on where you are in the world. Here in NZ 11KV is the normal HT feedline dropped from 33KV district feeders and where population densities are sufficient a single 11KV 3ph pole mounted transformer might feed a dozen dwellings each with a 60A 230VAC supply. In more urban areas the transformers are ground mounted still feeding 3 phases where domestic loads are shared on each phase to individual dwellings for best transformer load balancing.
In rural areas a 2 phase 11KV pole mounted transformer is often used where only a dwelling or 2 is need be supplied and they are always single phase output. It real remote areas just a single 11KV line is run so only a single phase secondary is possible of which this system is very reliant on a good ground/earth return.
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Practically every family house in Czechia (where I come from) or in Germany (where I live) has a 3-phase connection. It supplies electric stoves, owens, pumps, woodworking machines etc. My father has even 3-phase DIY electric mowing machine. :)
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When I got the electrical re-connected to my new house (demolished the old one) it was only the cost of the extra cable to get 3 phase instead of single phase.
Was about $400 from memory.
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If the current network is not set up for it the OP is expecting a 3rd cable to be run quite some distance at some cost to an electricity supplier that knows they will supply him with electricity either way. So yea, if you want it and they can provide it, it will cost you.
When I lived in Italy you only had 3kW, businesses and I think the public could apply for 4.5kW but you paid more for your power for ever more.
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need a few more wires but they can be smaller, pleny of places where everyone has 3 phase
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Wait, what?
I guess I'm ignorant but I honestly thought 3-phase was pretty much the universal standard for hooking up a house. I guess I just learned something new here. (again)
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Usually 3 phase is delivered to a substation that splits the single phases to different streets. It does not make economic sense to put all 3 phases down every street just in case one person wants it as it adds to the cabling required. No point in the OP going frantic. You want an industrial power supply? move to an industrial location.
I think you'll find that pretty much all of UK residential streets have a 3-phase supply running along them, whether they're above ground or buried. The odd exception might be a tiny rural group of houses that only justifies a single phase pole mounted transformer.
Buried street cables are 3 phase (and neutral outer sheath) with 2-3 adjacent houses tapped off each phase to balance the load. Ours is on the yellow phase (old colour coding convention).
Where there is above ground distribution, you will either see 4 wires (3 phases + Neutral) or the more modern twisted cable (as shown by Big Clive)...
https://www.youtube.com/watch?v=8JFfXZt7QoI (https://www.youtube.com/watch?v=8JFfXZt7QoI)
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Why can't I get any sweet and succulent 3 phase energy wired directly to my house?
The government and corporations are trying to hog all the 3 phase badassery to themselves. Sickening. We need to protest and fight back against this injustice.
It has a lot to do with zoning of your area and the infrastructure that is in place. Residential areas don't need 3 phase so it's not part of the infrastructure. Why add that extra cost to a zone if 3 phase probably won't be used. I don't know which part of the country your in but there are also City bylaws and Provincial laws that prevent industrial activity in residential zones. If you live outside a city limit then you should have no problem getting 3 phase installed . Or if you live in an older community like mine that has 3 phase from past industrial services . But even here it's slower being removed because it's not used anymore.
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There is a station at the end of my street, the cables run underground, I have two come up near my meter, no idea if there is a third. Just running a third from the road trunking to my house will have a cost that the power distributor will not just bear because I asked.
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That will be one phase and neutral, tapped off the 3 phase in the street (either that or an old defective feed that is disconnected - hard to say without a photo). Yes, they will charge you an arm and a leg to bring the other 2 phases from the street cable (buried, not trunked) onto your property and install 3 phase cable head!
It's actually about the only advantage of the more 'old fashioned' above ground distribution - they can use the IDC connectors that Big Clive shows, without even having to break into and joint the street cable.
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We have what 63A per house in the UK? that will do me. I don't need to run anything large enough to want 3 phase.
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Yes, the fuse holder in the DNO's cable head is normally marked 100A, but there's usually a 60A fuse fitted inside it.
EDIT: You can have it upgraded to a 100A service (fuse) at fairly nominal call-out charge if you want to get into multiple power showers and EV charging.
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Why can't I get any sweet and succulent 3 phase energy wired directly to my house?
I do not know your case of course.
What I have noticed is that for un-trained the difference in between single phase and three phase supply has nothing to do with higher powers. It is this mystic new high'er voltage that stops most of them from getting closer to 400VAC cabinet. I am not sure how this looks like on a scale of danger but definitely diy home playing with three phase has some additional gotchas included.
You can have it upgraded to a 100A service (fuse) at fairly nominal call-out charge if you want to get into multiple power showers and EV charging.
Energy losses in conductors are proportional to current squared so (100/60)^2 ~ 2.8 raise
So "fairly nominal call-out charge" and they are typically just upgrading fuse?
So either the cables have already been installed grossly oversized or now you are running cables smoking hot.
Upgrading cabling 2.8x is not cheap.
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You can have it upgraded to a 100A service (fuse) at fairly nominal call-out charge if you want to get into multiple power showers and EV charging.
Energy losses in conductors are proportional to current squared so (100/60)^2 ~ 2.8 raise
So "fairly nominal call-out charge" and they are typically just upgrading fuse?
So either the cables have already been installed grossly oversized or now you are running cables smoking hot.
Upgrading cabling 2.8x is not cheap.
The incomer buried cable should be rated for the 100A marked on the DNO (District Network Operator) incoming fuseholder. It might require upgrading of the meter tails if they're not already 25mm2. Most modern consumer units are rated for 100A.
The best time to do this sort of thing is when taking up your energy supplier's 'offer' of installing a free Smart Meter. The guy who fitted ours upgraded the tails and fitted a consumer side (after meter) 100A isolator switch for free when I asked him. Suppliers often charge quite a bit to visit site and fit an isolator (which tend to be fitted by default on new-builds). It pays to remember these things when getting a Smart Meter, they have everything on the van.
P.S. OT, but David Savery has a good rant about lack of mains isolator provision in the attached video. Start at 58:30 unless you also want the entertaining rant on worthless EICRs by useless electricians!
https://www.youtube.com/watch?v=37NXBGpahSo (https://www.youtube.com/watch?v=37NXBGpahSo)
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There is a station at the end of my street, the cables run underground, I have two come up near my meter, no idea if there is a third. Just running a third from the road trunking to my house will have a cost that the power distributor will not just bear because I asked.
Oh, they won't bear the cost, they'll charge you for it. Getting 3 phase installed where there is currently one will entail some digging in the street and between the street and your property to install new [direct burial] cabling. You'll pay a few thousand pounds for the pleasure.
BTW, it's two additional conductors - you've got one phase and neutral, they have to add another two phases. They aren't going to supply just the phases and no neutral. If the two conductors you already have were across two phases, as opposed to phase and neutral, they'd have \$220V \times \sqrt{3} = 380V \$ across them, not the 220V nominal that you're getting.
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Usually 3 phase is delivered to a substation that splits the single phases to different streets. It does not make economic sense to put all 3 phases down every street just in case one person wants it as it adds to the cabling required. No point in the OP going frantic. You want an industrial power supply? move to an industrial location.
Someone else has noted that it's normal to take the three phases and neutral down the whole street and tap different phases at different points for different building's supplies. It's quite possible that your next door neighbour is on a different phase - something to bear in mind if you're having a party in the garden and someone decides to throw an extension cord over the fence to power the disco lights from the neighbour's mains, while you power the music from your house's mains.
You're missing the fact that the OP is in North America, where a different system prevails. Rather than picking off individual phase+neutral pairs for each property, there's a centre tapped transformer, typically every 1-3 houses (primary connected across two of the three phases), usually on a pole. This supplies two phases at 180º from each other and a neutral. Each phase is nominally 120V with respect to the neutral and 240V with respect to each other. It's normal to bring two phases and a neutral in from the transformer, and bond the neutral to earth at the distribution board. Hefty appliances get a 240V supply, others 120V.
So, three phase is a wholesale change of supply in North America, not just bringing in the missing phases. You'll need a 3 phase transformer in place of the existing two phase.
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Usually 3 phase is delivered to a substation that splits the single phases to different streets. It does not make economic sense to put all 3 phases down every street just in case one person wants it as it adds to the cabling required. No point in the OP going frantic. You want an industrial power supply? move to an industrial location.
Someone else has noted that it's normal to take the three phases and neutral down the whole street and tap different phases at different points for different building's supplies. It's quite possible that your next door neighbour is on a different phase - something to bear in mind if you're having a party in the garden and someone decides to throw an extension cord over the fence to power the disco lights from the neighbour's mains, while you power the music from your house's mains.
You're missing the fact that the OP is in North America, where a different system prevails. Rather than picking off individual phase+neutral pairs for each property, there's a centre tapped transformer, typically every 1-3 houses (primary connected across two of the three phases), usually on a pole. This supplies two phases at 180º from each other and a neutral. Each phase is nominally 120V with respect to the neutral and 240V with respect to each other. It's normal to bring two phases and a neutral in from the transformer, and bond the neutral to earth at the distribution board. Hefty appliances get a 240V supply, others 120V.
So, three phase is a wholesale change of supply in North America, not just bringing in the missing phases. You'll need a 3 phase transformer in place of the existing two phase.
single phase, split phase is not two phase
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single phase, split phase is not two phase
I think you meant to say:
Single phase, split phase is not two phases.
When being pedantic, always check your spelling, punctuation and grammar. :) But yes, technically you are correct.
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Wow, is there ever a lot of misconceptions and misunderstandings surrounding this....
I'll take some pictures today once it gets light out to show how it's typically done around here.
Someone else has noted that it's normal to take the three phases and neutral down the whole street and tap different phases at different points for different building's supplies. It's quite possible that your next door neighbour is on a different phase - something to bear in mind if you're having a party in the garden and someone decides to throw an extension cord over the fence to power the disco lights from the neighbour's mains, while you power the music from your house's mains.
Wait... What?!!
Why would it matter if you use extension cords from mains supplied from different phases? You're not connecting anything across the phases or shorting them together. :wtf:
If your neighbor is on a different phase, it is no different than having two outlets in your own home supplied by different phases in all those homes over there that do have three phase.
You're missing the fact that the OP is in North America, where a different system prevails. Rather than picking off individual phase+neutral pairs for each property, there's a centre tapped transformer, typically every 1-3 houses (primary connected across two of the three phases), usually on a pole.
Uhh, no. First of all, the pole transformer is connected from one phase to the grounded neutral, NOT across phases. Most residential streets only have one phase strung along them. The feed lines between those streets that come from distribution will have all three, and individual streets are connected to different phases to balance out the load as seen from upstream.
While perhaps in some very rural setting you would have your own transformer for one house, here in the city it is typically more like 4-10+ houses per transformer when it is overhead and probably 20+ houses if it's underground buried lines. Small towns with larger properties (like my place at the lake where it is half an acre, the pole pig is shared between me and the house across the street) might share a transformer between just two or three properties, but that would be ridiculous in the city.
This supplies two phases at 180º from each other and a neutral. Each phase is nominally 120V with respect to the neutral and 240V with respect to each other.
Correct.
It's normal to bring two phases and a neutral in from the transformer, and bond the neutral to earth at the distribution board. Hefty appliances get a 240V supply, others 120V.
Almost correct. It's not two phases, it is a single centre-tapped phase, with the centre-tap grounded, often called "split-phase".
So, three phase is a wholesale change of supply in North America, not just bringing in the missing phases. You'll need a 3 phase transformer in place of the existing two phase.
That depends. If you're near something commercial, there will be three phase right there and it is just a matter of bringing in the other phases, although most commercial stuff or multi-unit residential units have their own dedicated transformers, sometimes on the commercial site itself, with the transformer owned by the customer, otherwise three pole mounted or a ground-pad-located transformer-in-box owned by the utility so you'd still be on the hook for some sort of transformer-installation-charge (even if you don't have to actually pay for the transformer itself) if you're using the power company's transformer(s).
The customer here is responsible for the service. For overhead installations here, the customer is responsible for supplying and installing the main panel and disconnect (usually an integrated panel which includes the main breaker for disconnect here for residential installations,) the feed to the meter base, the meter base itself and the feed wires up to the masthead, leaving at least 3-4 feet (I forget the exact spec) minimum of wire hanging out for them to be able to make connection and form proper drip loops. You can pretty much pick whatever amperage main breaker you want as long as you have the appropriate size feed conductors from masthead-meter-panel disconnect.
Long, LONG ago, like 1950s, you were allowed as low as 60A if you wanted. 70A then became the minimum (and strictly speaking is still allowed for VERY small dwellings like a single-bedroom apartment) but any normal single-family dwelling or one side of a duplex like mine that is over 700 sq. ft. is required to have a minimum 100A service. Most typical homes here are now usually built with a 200A main breaker and appropriate input wiring from the start.
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single phase, split phase is not two phase
I think you meant to say:
Single phase, split phase is not two phases.
When being pedantic, always check your spelling, punctuation and grammar. :) But yes, technically you are correct.
I'm no English expert but wouldn't it be ok to refer to a power system with two phases as "two phase" ? ;)
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I think you meant to say:
Single phase, split phase is not two phases.
When being pedantic, always check your spelling, punctuation and grammar. :) But yes, technically you are correct.
I'm no English expert but wouldn't it be ok to refer to a power system with two phases as "two phase" ? ;)
No, absolutely not!
Two phases would be 120° degrees apart!!
That would give you some intermediate voltage.
This is a center-tapped single phase, providing 180° separated 120-0-120
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single phase, split phase is not two phase
I think you meant to say:
Single phase, split phase is not two phases.
When being pedantic, always check your spelling, punctuation and grammar. :) But yes, technically you are correct.
I'm no English expert but wouldn't it be ok to refer to a power system with two phases as "two phase" ? ;)
If one is being pedantic, one would use single quotes or a hyphen to explicitly indicate that you're using a compound noun. In all seriousness, it's a "What does the local style guide say?" example, the disagreement in number looks wrong to some eyes to others it doesn't. So formally, it's either singular "a two-phase" or "two phases", but in truth nobody really cares (I have just angered every sub-editor on every English publication with that last phrase).
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I think you meant to say:
Single phase, split phase is not two phases.
When being pedantic, always check your spelling, punctuation and grammar. :) But yes, technically you are correct.
I'm no English expert but wouldn't it be ok to refer to a power system with two phases as "two phase" ? ;)
No, absolutely not!
Two phases would be 120° degrees apart!!
That would give you some intermediate voltage.
This is a center-tapped single phase, providing 180° separated 120-0-120
Somebody missed the "wink". He was taking the piss out of me (in a friendly fashion).
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... - something to bear in mind if you're having a party in the garden and someone decides to throw an extension cord over the fence to power the disco lights from the neighbour's mains, while you power the music from your house's mains.
Wait... What?!!
Why would it matter if you use extension cords from mains supplied from different phases? You're not connecting anything across the phases or shorting them together. :wtf:
Somebody missed the hint - disco lights on one phase, music system on the other - one generally connects the music system to the disco lights to make them flash in time. Sure, it's all fine if there are no faults or 'creative' wiring (I have seen, in real life, someone use more than one plug socket wired together to get a higher current feed out of a nominal 13A socket). I said "bear in mind" not, "this is a recipe for immediate disaster", don't blow what I said out of all proportion.
Uhh, no. First of all, the pole transformer is connected from one phase to the grounded neutral, NOT across phases. Most residential streets only have one phase strung along them. The feed lines between those streets that come from distribution will have all three, and individual streets are connected to different phases to balance out the load as seen from upstream.
I stand corrected. I've always assumed, when I've seen things like this:
(https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fwww.ul.com%2Fsites%2Fg%2Ffiles%2Fqbfpbp251%2Ffiles%2Fstyles%2Fhero_boxed_width%2Fpublic%2F2019-07%2FCT_EPT_Pole-Transformer_740x530.jpg%3Fitok%3DfaOEeJtT&f=1&nofb=1)
that all three phases were being used to keep balance. Three wires, three phases, seems natural to take the xformer primary's feeds from phase to phase.
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Somebody missed the "wink". He was taking the piss out of me (in a friendly fashion).
Nah, I saw it, but certain things that are fundamentally wrong drive me nuts, but I'm probably partially insane already anyway... ;)
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Practically every family house in Czechia (where I come from) or in Germany (where I live) has a 3-phase connection. It supplies electric stoves, owens, pumps, woodworking machines etc. My father has even 3-phase DIY electric mowing machine. :)
Same here. Every house has 3-phase available and even some apartments nowadays have all 3 phases available in one apartment.
In my parents home even my bedroom had 3x16A 3-phase outlet ;D
IIRC most of the mainland Europe is wired in this way.
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Somebody missed the "wink". He was taking the piss out of me (in a friendly fashion).
Nah, I saw it, but certain things that are fundamentally wrong drive me nuts, but I'm probably partially insane already anyway... ;)
so what was fundamentally wrong? two-phase power has two phases, three-phase power has three phases, split-phase is a single phase because 180deg doesn't count as a seperate phase
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IIRC most of the mainland Europe is wired in this way.
From my experience that's true for all the north western European countries (roughly everybody on the Baltic and North Seas). It's not for the UK, where a single phase is normal in individual dwellings. I can't speak for the counties with a Mediterranean coast, for some reason I've never been near a distribution panel to look in those places.
What happens in middle Europe is anybody's guess (You could take that as a general philosophical statement. :) ) I expect someone will be along to enlighten us shortly.
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Two phases would be 120° degrees apart!!
That would give you some intermediate voltage.
This is a center-tapped single phase, providing 180° separated 120-0-120
The center-tapped single phase creates a 2-phase system. But if you have two phases out of a 3-phase system, then those two are 120° apart. And if the power distribution is based on a 3-phase system while each phase powers a transformer with a center-tapped output, then you've basically created a 6-phase system. Of course, each house has only access to its local center-tapped single phase. BTW, some industries use special multi-phase systems with much more than three phases to power huge motors. Typically they operate dedicated multi-phase generators for that purpose as they get only a 3-phase system from the power grid.
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Not outraged at all, however I am 85% convinced that the traditional 3 phase grid is no longer appropriate, and probably wasteful a lot in terms of energy loss and all the complexity to control it these days.
Existing 3 phase generation should be converted to DC at point of generation.
The transmission grids would become 3 wire split DC, loosely regulated, with relaxed voltage control tolerances,
and regional DC storage that can support outages for short periods.
Voltage step -down and regulation would be by inverters.
In our residence there are about 50 appliances and most convert to DC at the input as we know. Of the appliances that have motors, most either are or could be BLDC etc.
Similar applies in industrial consumption. VFDs with DC links are either common, or should be, replacing remaining MV 3 phase machines.
I read the magazine 'Pac-World". The increasing complexity of Protection and Control,
is mainly to support the deficiencies, trying control instability of the aging 3 phase technologies (sinewave synchronization etc)
I think obtaining the required reliablity with a loosely regulated DC transmission system would be a lot simpler.
It is happening. India has (I think) world's largest, longest HVDC link just commissioned, and is talking about further 50 GW DC linkage across country.
China is doing similar.
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so what was fundamentally wrong? two-phase power has two phases, three-phase power has three phases, split-phase is a single phase because 180deg doesn't count as a seperate phase
Show me anywhere that you find a two phase supply to a site externally from the power company. :)
Here, there is really only one situation where you see a two-phase, 120° supply, which makes it 208 volts to your range, clothes drier, etc. (and appliances here ARE rated for 240/208 with different wattage ratings) and that is a multi-unit apartment or condo building with more than, say, about 6 units, where they have a three phase supply to the actual building, but then each unit only has a standard two-pole-style residential panel instead of a commercial-style three-phase panel, where each individual unit is connected to two of the phases, balanced by the connections to each of the various units.
You can't get an actual two-phase from the power company. You only end up with that when you run a device intended for split-phase 240 off two legs of the incoming three-phase.
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Two phases would be 120° degrees apart!!
That would give you some intermediate voltage.
This is a center-tapped single phase, providing 180° separated 120-0-120
The center-tapped single phase creates a 2-phase system. But if you have two phases out of a 3-phase system, then those two are 120° apart. And if the power distribution is based on a 3-phase system while each phase powers a transformer with a center-tapped output, then you've basically created a 6-phase system. Of course, each house has only access to its local center-tapped single phase. BTW, some industries use special multi-phase systems with much more than three phases to power huge motors. Typically they operate dedicated multi-phase generators for that purpose as they get only a 3-phase system from the power grid.
center-tapped is not two phases, 180deg doesn't count. you don't need special generators to generate more phases as soon as you have atleast two, all other phase angles can be created with linear combinations
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Somebody missed the hint - disco lights on one phase, music system on the other - one generally connects the music system to the disco lights to make them flash in time. Sure, it's all fine if there are no faults or 'creative' wiring (I have seen, in real life, someone use more than one plug socket wired together to get a higher current feed out of a nominal 13A socket). I said "bear in mind" not, "this is a recipe for immediate disaster", don't blow what I said out of all proportion.
The only time that would be a problem would be a severe ground fault due to total lack of ground on one system and some sort of fault. Maybe this is a common occurrence over there, hence the reason that you require an RCD/GFCI on the whole premises? That wouldn't be any different, though, whether or not your neighbor is on the same phase as you or not. If one of your neutrals is lifted above ground, it doesn't really matter whether it is single or three phases, the problem is the neutral not being at ground potential, and THAT is DANGEROUS!
Here we actually ground everything. Every power pole is grounded to its own ground rod. Every service entrance is grounded to a copper water main or ground rod or ground plate, etc and bonded to the neutral at the service entrance.
Uhh, no. First of all, the pole transformer is connected from one phase to the grounded neutral, NOT across phases. Most residential streets only have one phase strung along them. The feed lines between those streets that come from distribution will have all three, and individual streets are connected to different phases to balance out the load as seen from upstream.
I stand corrected. I've always assumed, when I've seen things like this:
(https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fwww.ul.com%2Fsites%2Fg%2Ffiles%2Fqbfpbp251%2Ffiles%2Fstyles%2Fhero_boxed_width%2Fpublic%2F2019-07%2FCT_EPT_Pole-Transformer_740x530.jpg%3Fitok%3DfaOEeJtT&f=1&nofb=1)
that all three phases were being used to keep balance. Three wires, three phases, seems natural to take the xformer primary's feeds from phase to phase.
No, that photo above is the three transformers supplying a full three-phase supply to commercial or large residential customers. A standard residential street would only have one transformer, so there would only be three outgoing wires instead of four like in that photo. (120 120 and neutral)
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center-tapped is not two phases, 180deg doesn't count. you don't need special generators to generate more phases as soon as you have atleast two, all other phase angles can be created with linear combinations
And how would you design a multi-phase motor for that? All windings have to be same and they have to be powered by the same voltage.
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so what was fundamentally wrong? two-phase power has two phases, three-phase power has three phases, split-phase is a single phase because 180deg doesn't count as a seperate phase
Show me anywhere that you find a two phase supply to a site externally from the power company. :)
Here, there is really only one situation where you see a two-phase, 120° supply, which makes it 208 volts to your range, clothes drier, etc. (and appliances here ARE rated for 240/208 with different wattage ratings) and that is a multi-unit apartment or condo building with more than, say, about 6 units, where they have a three phase supply to the actual building, but then each unit only has a standard two-pole-style residential panel instead of a commercial-style three-phase panel, where each individual unit is connected to two of the phases, balanced by the connections to each of the various units.
You can't get an actual two-phase from the power company. You only end up with that when you run a device intended for split-phase 240 off two legs of the incoming three-phase.
Its possible if you live in some weird places like Norway.
Unlike most of EU where mains is 230V star 3 phase they have 230V delta 3 phase. This means they get 230V between phases and its actually only like 135V on each phase, but not that it matters because they don't bring the neutral to the house. All of the normal single phase loads are wired across two phases and the cirucit breakers are all double pole to disconnect both. This causes major problems when you want to run a real 3 phase load like a motor that was made anywhere else.
So its kind of like a wierd in between of the EU 3 phase system and the US split phase system. Its a pretty stupid system where the only benifit is saving 1 wire for neutral.
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center-tapped is not two phases, 180deg doesn't count. you don't need special generators to generate more phases as soon as you have atleast two, all other phase angles can be created with linear combinations
And how would you design a multi-phase motor for that? All windings have to be same and they have to be powered by the same voltage.
transformers
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The center-tapped single phase creates a 2-phase system.
Well, you can call it whatever the fuck you want on your side of the pond, I suppose, but here that is ALWAYS considered EXPLICITLY WRONG. You would probably be thrown off the jobsite here for saying things like that because it would be obvious you don't know what you're talking about and that's how people get killed. It is NOT two phases! It is one single phase from the supply, just center tapped. Here, you never, ever, ever call that two phases, that would refer to TWO of the actual MAIN supply phases. :)
But if you have two phases out of a 3-phase system, then those two are 120° apart. And if the power distribution is based on a 3-phase system while each phase powers a transformer with a center-tapped output, then you've basically created a 6-phase system. Of course, each house has only access to its local center-tapped single phase. BTW, some industries use special multi-phase systems with much more than three phases to power huge motors. Typically they operate dedicated multi-phase generators for that purpose as they get only a 3-phase system from the power grid.
No, no no...
You wouldn't ever have three center tapped transformers feeding a site. If you get a three phase supply, it is three different, non-center-tapped transformers supplying 120-120-120, hence the reason you get 208V for commercial/industrial stuff... Our typical 3-phase motors and stuff run on 208V from the 120-120-120 that can also be used to power individual loads instead of the 380-415V you folks use, unless you go up to one of the industrial supplies where things like 480 or 600V are used for very large motors, etc. but that would be a separate service, or more likely, a site where they own their own transformers, at least one supplying 120-120-120(/208) for normal loads and then another at 277/480, etc.
Many office buildings are wired with 277V lighting to reduce transformer requirements when they have a transformer on each floor, etc. That is relatively common, but things like electrical boxes and switches are different dimensions (the box is taller) so they cannot be intermingled with the vast majority of stuff that is rated 250V MAX.
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Not outraged at all, however I am 85% convinced that the traditional 3 phase grid is no longer appropriate, and probably wasteful a lot in terms of energy loss and all the complexity to control it these days.
Existing 3 phase generation should be converted to DC at point of generation.
The transmission grids would become 3 wire split DC, loosely regulated, with relaxed voltage control tolerances,
and regional DC storage that can support outages for short periods.
Voltage step -down and regulation would be by inverters.
Let me guess... you own a lot of stock in power semiconductor manufacturers? ::)
Large transformers are relatively efficient, cheap and reliable.
Change that to giant inverters everywhere? Really? :palm:
Run all 3-phase induction motors off VFDs from now on?! There's a reason they work so well on three phase, the rotating currents make a continuous stream.
Long distance, high voltage transmission is a completely different animal! DC has some advantages there but the task of conversion and the conversion losses are non trivial.
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Let me guess... you own a lot of stock in power semiconductor manufacturers? ::)
Large transformers are relatively efficient, cheap and reliable.
Change that to giant inverters everywhere? Really? :palm:
Run all 3-phase induction motors off VFDs from now on?! There's a reason they work so well on three phase, the rotating currents make a continuous stream.
Long distance, high voltage transmission is a completely different animal! DC has some advantages there but the task of conversion and the conversion losses are non trivial.
Hi drussell, Your comments more or less reinforce my opinion.
I was involved not as stock holder, but just as engineer, with large industrial semiconductor inverters,
some installation rated up to about 20 MW.
Other inverters rated 5MW at 100 kHz using IGBT.
As these were powered by similarly rated 6 phase 50/60 Hz transformers, I am aware of the cost comparisons between the iron devices and the semiconductor devices.
And furthermore aware the significant reductions in transformer cost as frequency rises.
A 30 kHz 10 MVA transformer would fit in the trunk of your car.
The ratings I mention above are not yet at grid distribution level,
but in my opinion that industrial technology is now ready to be scaled into the 200's MW level that are required for the newer power generation technologies.
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I'm with James on this. I used to be outraged because there was a lot of surplus 3 phase equipment that I lusted after at very attractive prices, but not usable because 3 phase installation was outrageous (not unjustified, just way more than the cost of some fairly major gear) and the cost of rotary converters and other options was nearly as bad and consumed a lot of space. Now that VFDs are capable and relatively inexpensive I don't care anymore.
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Somebody missed the hint - disco lights on one phase, music system on the other - one generally connects the music system to the disco lights to make them flash in time. Sure, it's all fine if there are no faults or 'creative' wiring (I have seen, in real life, someone use more than one plug socket wired together to get a higher current feed out of a nominal 13A socket). I said "bear in mind" not, "this is a recipe for immediate disaster", don't blow what I said out of all proportion.
The only time that would be a problem would be a severe ground fault due to total lack of ground on one system and some sort of fault. Maybe this is a common occurrence over there, hence the reason that you require an RCD/GFCI on the whole premises? That wouldn't be any different, though, whether or not your neighbor is on the same phase as you or not. If one of your neutrals is lifted above ground, it doesn't really matter whether it is single or three phases, the problem is the neutral not being at ground potential, and THAT is DANGEROUS!
Here we actually ground everything. Every power pole is grounded to its own ground rod. Every service entrance is grounded to a copper water main or ground rod or ground plate, etc and bonded to the neutral at the service entrance.
What did I say about not blowing things up out of all proportion?
As for earthing. Glass houses and all that.
NEMA 1-15R receptacle, legal for new builds until 1968, met code until 1972.
(https://external-content.duckduckgo.com/iu/?u=http%3A%2F%2Fimages.fruitridgetools.com%2FImages%2FCWD736W-EA-NOBOX-2.JPG&f=1&nofb=1)
BS546 plugs - note the huge earth pin, current from 1934 up to 1947 when the standard was changed to ...
(https://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/BS_546_Plugs_-_15A_5A_2A.png/440px-BS_546_Plugs_-_15A_5A_2A.png)
BS1363 (The foot stabber)
(https://upload.wikimedia.org/wikipedia/commons/f/f7/Moulded_and_rewireable_BS_1363_plugs_%28horizontal%29.jpg)
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NEMA 1-15R receptacle, legal for new builds until 1968, met code until 1972.
(https://external-content.duckduckgo.com/iu/?u=http%3A%2F%2Fimages.fruitridgetools.com%2FImages%2FCWD736W-EA-NOBOX-2.JPG&f=1&nofb=1)
HAHA, that's sure a weird looking version of a NEMA 1-15... Usually the two prongs are centered vertically instead of being based on a back housing that could support the ground prong. :) Makes sense, though, since production must be extremely limited on those by now.
Those are still available here for replacement purposes where a circuit is supplied by a legacy 2-wire, un-grounded cable and it is impractical to fish a ground wire to the box. They are still valid and allowed, just not for new installations. Most of the time though, for retrofit people go with a GFCI with the ground left open, which last time I checked that specifically, was still allowed as long as you put the little stickers on any downstream plugs that you put a 3-prong plug on which doesn't actually have the ground connected. It is certainly sub-optimal, and you lose any shielding effect for devices with a grounded chassis, but it is allowed. ;)
I could go over to Home Depot right now and buy one.
(They're like $10 each instead of the $0.50 for a regular receptacle, but they're still there on the shelf. :))
EDIT:
As for earthing. Glass houses and all that.
I was talking about the whole system being above ground due to some fault.
We still use plenty of two-prong extension cords and devices over here. Your disco-lights or music system from the example might not even have a ground, though if it's professional level gear it will, and then, yeah, you're back to grounds which aren't actually grounds or minor differences between panels causing ground loops, etc. Welcome to being a pro sound and lighting engineer, we fight that crap all the time on gigs. But that has nothing to do with three phase vs single phase. The same issue exists either way. :)
Most small things around here don't require the actual ground, but your neutral sure should still be at ground potential.
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BS546 plugs - note the huge earth pin, current from 1934 up to 1947 when the standard was changed
The 15a variant is still widely used thought the uk as the connector of choice for theater dimmer circuits.
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BS546 plugs - note the huge earth pin, current from 1934 up to 1947 when the standard was changed
The 15a variant is still widely used thought the uk as the connector of choice for theater dimmer circuits.
I have fought to plug in more 15A plugs that were just in reach while teetering on a 15 foot ladder and clutching a length of 2" steel piping than I care to remember. The 2A variant is still current domestic usage for things like plugged standard lamps on switched lighting circuits. There's one not three feet from me.
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Someone else has noted that it's normal to take the three phases and neutral down the whole street and tap different phases at different points for different building's supplies. It's quite possible that your next door neighbour is on a different phase - something to bear in mind if you're having a party in the garden and someone decides to throw an extension cord over the fence to power the disco lights from the neighbour's mains, while you power the music from your house's mains.
You're missing the fact that the OP is in North America, where a different system prevails. Rather than picking off individual phase+neutral pairs for each property, there's a centre tapped transformer, typically every 1-3 houses (primary connected across two of the three phases), usually on a pole. This supplies two phases at 180º from each other and a neutral. Each phase is nominally 120V with respect to the neutral and 240V with respect to each other. It's normal to bring two phases and a neutral in from the transformer, and bond the neutral to earth at the distribution board. Hefty appliances get a 240V supply, others 120V.
So, three phase is a wholesale change of supply in North America, not just bringing in the missing phases. You'll need a 3 phase transformer in place of the existing two phase.
In my (typical suburban America) neighborhood the main arterial road between towns has 7200V 3 phase run along it. One of those phases is tapped off and run underground to feed my neighborhood, it then feeds pad mounted transformers that are mostly buried in vegetation a few feet behind the sidewalk, each of those powers anywhere from 2 to 6 houses. This is a very typical arrangement, residential streets sprouting off from arterials will get a single phase off of the nearest 3 phase distribution feed, they stagger them to keep the load balanced. It's not unheard of for there to be all three phases running down a street with houses, but I've never seen a house in North America that had 3 phase power. Apparently in some agricultural areas it is done occasionally.
Larger buildings are almost always 3 phase, even residential apartments will have a 3 phase feed but only two phases will be brought into each unit, wired to standard split phase domestic panels. This results in 208V instead of the usual 240V for higher powered loads, so things like clothes dryers, kitchen stoves and water heaters and wall heaters are slower than they would be in a typical house. Most of the time standard 240V appliances are used.
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Somebody missed the "wink". He was taking the piss out of me (in a friendly fashion).
Nah, I saw it, but certain things that are fundamentally wrong drive me nuts, but I'm probably partially insane already anyway... ;)
so what was fundamentally wrong? two-phase power has two phases, three-phase power has three phases, split-phase is a single phase because 180deg doesn't count as a seperate phase
Whatever is grammatically most correct doesn't really matter, colloquially at least it is referred to as "single phase power" and technical people know that it is a single split phase.
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NEMA 1-15R receptacle, legal for new builds until 1968, met code until 1972.
(https://external-content.duckduckgo.com/iu/?u=http%3A%2F%2Fimages.fruitridgetools.com%2FImages%2FCWD736W-EA-NOBOX-2.JPG&f=1&nofb=1)
HAHA, that's sure a weird looking version of a NEMA 1-15... Usually the two prongs are centered vertically instead of being based on a back housing that could support the ground prong. :) Makes sense, though, since production must be extremely limited on those by now.
Those weird ones are what's available now for replacements. When we were preparing my late grandmother's house to be sold I had to replace a few receptacles in the original ungrounded portion of the house and those were all I could get. They're made that way because it's cheap, they use all the same molded parts as the standard 3 prong receptacles but don't install the ground contacts and the face doesn't have the opening. I think they look stupid but I guess I can understand not making a niche item like ungrounded NEMA-15 receptacles the same way they used to.
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Someone else has noted that it's normal to take the three phases and neutral down the whole street and tap different phases at different points for different building's supplies. It's quite possible that your next door neighbour is on a different phase - something to bear in mind if you're having a party in the garden and someone decides to throw an extension cord over the fence to power the disco lights from the neighbour's mains, while you power the music from your house's mains.
I once worked in a Lab where we discovered that adjacent workbenches were on different phases! :scared:
415V 3 phase ceiling drop to the end of each row of three benches and... :palm:
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Usually 3 phase is delivered to a substation that splits the single phases to different streets. It does not make economic sense to put all 3 phases down every street just in case one person wants it as it adds to the cabling required. No point in the OP going frantic. You want an industrial power supply? move to an industrial location.
That is not unfortunately the full truth.
Calculate how much power you can transfer with a single phase using amount X of copper. Then calculate same, using the same amount X of copper split for three phases.
As what you said, is a mathematically proven nonsense. Also, having separate loads on each phase create load imbalances and a lot more issues and stupid inconveniences.
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Whatever is grammatically most correct doesn't really matter, colloquially at least it is referred to as "single phase power" and technical people know that it is a single split phase.
Single phase... Sure... Split phase... Sure!
It is just most certainly not TWO PHASE! :)
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Someone else has noted that it's normal to take the three phases and neutral down the whole street and tap different phases at different points for different building's supplies. It's quite possible that your next door neighbour is on a different phase - something to bear in mind if you're having a party in the garden and someone decides to throw an extension cord over the fence to power the disco lights from the neighbour's mains, while you power the music from your house's mains.
I once worked in a Lab where we discovered that adjacent workbenches were on different phases! :scared:
415V 3 phase ceiling drop to the end of each row of three benches and... :palm:
So what? There is exactly 0 issues with that.
Even for the garden party, there is absolutely 0 issues supplying AV tech from different phases. What may be a real issue tho, is you may have two different potential in between yo grounds/neutrals, if you bring the power from two very different places. Big AV setups are alway powered from threephase anyway.
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Those weird ones are what's available now for replacements. When we were preparing my late grandmother's house to be sold I had to replace a few receptacles in the original ungrounded portion of the house and those were all I could get. They're made that way because it's cheap, they use all the same molded parts as the standard 3 prong receptacles but don't install the ground contacts and the face doesn't have the opening. I think they look stupid but I guess I can understand not making a niche item like ungrounded NEMA-15 receptacles the same way they used to.
Indeed.
That's much stated much more clearly than my attempt above. :)
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Someone else has noted that it's normal to take the three phases and neutral down the whole street and tap different phases at different points for different building's supplies. It's quite possible that your next door neighbour is on a different phase - something to bear in mind if you're having a party in the garden and someone decides to throw an extension cord over the fence to power the disco lights from the neighbour's mains, while you power the music from your house's mains.
I once worked in a Lab where we discovered that adjacent workbenches were on different phases! :scared:
415V 3 phase ceiling drop to the end of each row of three benches and... :palm:
So what? There is exactly 0 issues with that.
Even for the garden party, there is absolutely 0 issues supplying AV tech from different phases. What may be a real issue tho, is you may have two different potential in between yo grounds/neutrals, if you bring the power from two very different places. Big AV setups are alway powered from threephase anyway.
Exactly!
I don't understand that the problem would be, or the reason for the facepalms??! :-//
That is all perfectly normal, other than any potential ground loops.
It has nothing to do with the number of phases on the supply.
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Usually 3 phase is delivered to a substation that splits the single phases to different streets. It does not make economic sense to put all 3 phases down every street just in case one person wants it as it adds to the cabling required. No point in the OP going frantic. You want an industrial power supply? move to an industrial location.
That is not unfortunately the full truth.
Calculate how much power you can transfer with a single phase using amount X of copper. Then calculate same, using the same amount X of copper split for three phases.
As what you said, is a mathematically proven nonsense. Also, having separate loads on each phase create load imbalances and a lot more issues and stupid inconveniences.
I don't understand what you're getting at there.... Could you elaborate a little, please?
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Someone else has noted that it's normal to take the three phases and neutral down the whole street and tap different phases at different points for different building's supplies. It's quite possible that your next door neighbour is on a different phase - something to bear in mind if you're having a party in the garden and someone decides to throw an extension cord over the fence to power the disco lights from the neighbour's mains, while you power the music from your house's mains.
I once worked in a Lab where we discovered that adjacent workbenches were on different phases! :scared:
415V 3 phase ceiling drop to the end of each row of three benches and... :palm:
So what? There is exactly 0 issues with that.
Even for the garden party, there is absolutely 0 issues supplying AV tech from different phases. What may be a real issue tho, is you may have two different potential in between yo grounds/neutrals, if you bring the power from two very different places. Big AV setups are alway powered from threephase anyway.
Exactly!
I don't understand that the problem would be, or the reason for the facepalms??! :-//
That is all perfectly normal, other than any potential ground loops.
It has nothing to do with the number of phases on the supply.
Because it was back in the '80s, pre RCD days. We would often have extension blocks strung between benches, lots of test gear, High power RF amplifier development and 415V between the live pins on adjacent mains 13A sockets.
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Whatever is grammatically most correct doesn't really matter, colloquially at least it is referred to as "single phase power" and technical people know that it is a single split phase.
Single phase... Sure... Split phase... Sure!
It is just most certainly not TWO PHASE! :)
Given two sinusoidal signals of amplitude \$V : A = V sin (\omega t + \phi_1) \text{ and } B = V sin (\omega t + \phi_2) \text { where } \phi_1 \neq \phi_2 \$ we would say that we were presented with two phases. The phase angles are different.
Why is this a special case when \$ \phi_1 \neq \phi_2 \text{ and } \phi_1 = 0, \phi_2 = \pi\$?
>:D
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Because it was back in the '80s
for once the uk wiring regs got sensible,it used to be no outlets on a different phase less than 6 foot apart,then it was allowed as long as you fitted warning labels,now it dont matter
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Well, you can call it whatever the fuck you want on your side of the pond, I suppose, but here that is ALWAYS considered EXPLICITLY WRONG. You would probably be thrown off the jobsite here for saying things like that because it would be obvious you don't know what you're talking about and that's how people get killed. It is NOT two phases! It is one single phase from the supply, just center tapped. Here, you never, ever, ever call that two phases, that would refer to TWO of the actual MAIN supply phases. :)
What is the reasoning behind "split-phase != 2-phase system"? Both legs of the US split-phase give you 120V to neutral and 240V between the legs. A 3-phase system works exactly the same, just with a different phase angle and therefore a different voltage between phases. And it's the same story for a multi-phase system with more than three phases. The phases are 360°/n apart (n = number of phases).
You wouldn't ever have three center tapped transformers feeding a site.
I have never claimed that! That was a theoretical contemplation and I clearly stated:
"Of course, each house has only access to its local center-tapped single phase".
Please try to think about the basic idea! Each phase of a 3-phase HV grid powers a split-phase pole transformer (input: phase to neutral/earth, output: split-phase with the center-tap connected to neutral/earth). So all the output's center-taps are connected (your reference point). That means the top legs are 120° degrees apart, same for the bottom legs. And since top and bottom legs are 180° apart you get six phases, theoretically.
If you get a three phase supply, it is three different, non-center-tapped transformers supplying 120-120-120, hence the reason you get 208V for commercial/industrial stuff.
I don't disagree. ;)
Edit:
I think I found the reason for the misunderstanding of 2-phase systems. There is a 2-phase system with the two phases 90° apart, which is created by a Scott-T transformer fed by a 3-phase system.
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Because it was back in the '80s
for once the uk wiring regs got sensible,it used to be no outlets on a different phase less than 6 foot apart,then it was allowed as long as you fitted warning labels,now it dont matter
Haha, that's pretty funny, although I suppose you COULD try to stick your finger in both sockets at once for a really cool hairdo at your voltages. :)
Here, for decades our kitchen counter plugs have normally been required to have both phases available on a single plug, so if you casually stick your fork tine or skewer or whatever in the top HOT and another in the bottom HOT of a duplex plug, you get a marginally nifty 240V hairdo, but probably not quite the same as the one you have when you wake up from the smouldering slam against the wall that you folks would get from what would be your 380+ volt ZAP!
(https://nicholsnotes.com/wp-content/uploads/2015/12/Static-Hair.jpg)
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Yep. Faults and bodges could happen (more so back then). It should be safe, as long as you're aware of it... We weren't.
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Here, for decades our kitchen counter plugs have normally been required to have both phases available on a single plug, so if you casually stick your fork tine or skewer or whatever in the top HOT and another in the bottom HOT of a duplex plug, you get a marginally nifty 240V hairdo, but probably not quite the same as the one you have when you wake up from the smouldering slam against the wall that you folks would get from what would be your 380+ volt ZAP!
Thankfully, you can't put a fork or a skewer in ours..
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Here, for decades our kitchen counter plugs have normally been required to have both phases available on a single plug, so if you casually stick your fork tine or skewer or whatever in the top HOT and another in the bottom HOT of a duplex plug, you get a marginally nifty 240V hairdo, but probably not quite the same as the one you have when you wake up from the smouldering slam against the wall that you folks would get from what would be your 380+ volt ZAP!
Thankfully, you can't put a fork or a skewer in ours..
Are you sure about that? Sounds like a challenge! :)
We have tamper-resistant sockets as a requirement here now too (I hate them with a passion) but if you think someone can't push in the ground protector door to defeat it just like the ground prong does, I guess you've not been around enough curious younglings or drunk teenagers or whatnot... ;D
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Because it was back in the '80s, pre RCD days. We would often have extension blocks strung between benches, lots of test gear, High power RF amplifier development and 415V between the live pins on adjacent mains 13A sockets.
How else would you do it though? If you've got a 3 phase drop to a row of benches you're going to either have the entire load on one phase, or you'll have adjacent benches on different phases somewhere in the row.
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I was shocked when somebody wrote that it is normal to have 200A single phase supply to the house :o :o These are ridicoulous currents for domestic supply... I just cant understand why they are not using 3 phase supply in america
As others wrote, in europe every building has a 3 phase power supply, here most common main fuses are 3x20A or 3x25A. Now compare that to single phase on 110V :o
And everything is so simple, as you have the same voltages everywhere. 230V/400V in your own house/worklab, same in industry. In industry most of equipment is on the same voltage level, of course some big motors are running on medium voltage.
The beautiful thing is that i can test most of industrial equipment anywhere i am...
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Thankfully, you can't put a fork or a skewer in ours..
No, but you can open the shutter with a screwdriver into the ground socket and insert stripped wires into the other two sockets. Removing the screwdriver will hold the two wires in place.
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Because it was back in the '80s, pre RCD days. We would often have extension blocks strung between benches, lots of test gear, High power RF amplifier development and 415V between the live pins on adjacent mains 13A sockets.
How else would you do it though? If you've got a 3 phase drop to a row of benches you're going to either have the entire load on one phase, or you'll have adjacent benches on different phases somewhere in the row.
Put them on a single phase and use the other phases for lighting, heating, aircon etc. Either that or use different phases either side of the central corridor (there was no need to drop 3 phases for 3 benches).
Actually that building had very poor phase balance anyway. It was a converted tyre warehouse with a suspended ceiling added (no expense spared for engineers working on mil stuff). The main supplier fuses in the cable head blew with monotonous regularity and the housing had distorted and was leaking pitch from the heat. The company wouldn't stump up for a higher current feed (I'm not sure that outlying bit of the industrial estate would support it).
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I was shocked when somebody wrote that it is normal to have 200A single phase supply to the house :o :o These are ridicoulous currents for domestic supply... I just cant understand why they are not using 3 phase supply in america
As others wrote, in europe every building has a 3 phase power supply, here most common main fuses are 3x20A or 3x25A. Now compare that to single phase on 110V :o
And everything is so simple, as you have the same voltages everywhere. 230V/400V in your own house/worklab, same in industry. In industry most of equipment is on the same voltage level, of course some big motors (1MW) are running on 6kV.
The beautiful thing is that i can test any industrial equipment anywhere i am...
200A 240V service is the standard for houses in the USA and has been for around 40 years, I don't think you can even install anything smaller in new construction. Larger houses sometimes have 400A, especially in areas that do not have natural gas service and thus need a lot of power for electric heating. I have even seen a few very large houses with 600A service, the sort of places that would qualify as mansions, these are still single phase. I don't think it really matters though, for 99.9% of the population they plug a device into a wall socket, it works and they are happy. They don't know anything about phases and they don't care, nor have any reason to care. If I were designing the whole system from scratch then 3 phase would be a natural choice, but it is all built upon decades of legacy equipment. The USA electrified very early relative to much of the world, so we were building upon the oldest and most primitive system. Countries that started later had the benefit of starting out with more modern technology and not having to worry about compatibility with existing infrastructure. You see this sort of thing all over, not just in power.
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I was shocked when somebody wrote that it is normal to have 200A single phase supply to the house :o :o These are ridicoulous currents for domestic supply... I just cant understand why they are not using 3 phase supply in america
As others wrote, in europe every building has a 3 phase power supply, here most common main fuses are 3x20A or 3x25A. Now compare that to single phase on 110V :o
It isn't single phase 120V!... :palm:
It is 240V centre-tapped to 120-0-120, so the main breaker is 2x200A, so that is 400A total available at 120V or 200A total at 240V.
Apparently we usewaste far more electricity on average than you folks do. 8)
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Thankfully, you can't put a fork or a skewer in ours..
No, but you can open the shutter with a screwdriver into the ground socket and insert stripped wires into the other two sockets. Removing the screwdriver will hold the two wires in place.
US code now requires "tamper resistant" receptacles in homes here too, they have shutters similar to the UK sockets. I don't like them personally, they cost as much as commercial grade stuff but are built like the cheap builder grade devices and sometimes it's hard to get some plugs to go in properly. It's easier to just not poke stuff into wall sockets. The live slot is small enough already that most metal objects like forks and coins and such won't go in anyway, stuff like hairpins and straightened paperclips, well a determined child will figure out how to open the shutters on UK receptacles anyway. I tend to view it as evolution in action. I've never known anyone who has known anyone who has had a kid electrocuted, it's pretty low on the list of household risks.
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It isn't single phase 120V!... :palm:
It is 240V centre-tapped to 120-0-120, so the main breaker is 2x200A, so that is 400A total available at 120V or 200A total at 240V.
Apparently we usewaste far more electricity on average than you folks do. 8)
North American houses are gigantic by European standards. My 2200 sqft 3 bedroom split level is very modest, it was considered a starter home when it was built in 1979. Even the tiny single floor houses that sprouted up like weeds in the post-WWII building boom are bigger than typical European dwellings. Geography that has historically offered vast amounts of space and abundant resources led to a culture of large (by world standards) homes.
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Anyone Else Outraged About 3 Phase? Short answer is no. If you really have a justification for needing a 3-phase supply it's probably already there, either overhead lines or underground, you just have to pay for the connection. An engineer would have done his or her homework and used some common sense whereas a troll would throw a hissy fit. Just my 2cent worth.
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It isn't single phase 120V!... :palm:
It is 240V centre-tapped to 120-0-120, so the main breaker is 2x200A, so that is 400A total available at 120V or 200A total at 240V.
Apparently we usewaste far more electricity on average than you folks do. 8)
North American houses are gigantic by European standards. My 2200 sqft 3 bedroom split level is very modest, it was considered a starter home when it was built in 1979. Even the tiny single floor houses that sprouted up like weeds in the post-WWII building boom are bigger than typical European dwellings. Geography that has historically offered vast amounts of space and abundant resources led to a culture of large (by world standards) homes.
True, our styles of construction are very different. We build houses much more energy efficently. Nowadays it is standard to have 15-25cm or even more insulation on the outer skin of the house, with a lot of details to minimize the losses. We dont use electricity to heat directly, but instead use natural gas, heat pumps or wood for heating. We use very little energy for cooling also, i don't even have an AC and i dont need it even in the middle of the summer when there is 30-35°C. I heat the house with wood gasification boiler (with lambda control), coupled with 2000l heat acumulator, meaning that i use minimum electricity for the heating (only the consumption of boiler fan, water pumps and electronics)
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I'm not paying a single dollar of tax money until some 3 phase power comes zipping on through to my location.
WHOS WITH ME!!
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It is 240V centre-tapped to 120-0-120, so the main breaker is 2x200A, so that is 400A total available at 120V or 200A total at 240V.
Over here a single-family home has usually 35A (3*35A at 230V) or 63A (3*63A at 230V) main breakers based on the local power company. An apartment building with two or three flats mostly has 63A main breakers and 35A breakers for each flat.
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well a determined child will figure out how to open the shutters on UK receptacles anyway
In the uk the kids are assisted by the do gooders who tried to make everyone fit "safety "covers to sockets
(https://www.electriciancourses4u.co.uk/wp-content/uploads/fatally-flawed-socket.jpg)
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I'm not paying a single dollar of tax money until some 3 phase power comes zipping on through to my location.
Good luck with that...
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The USA electrified very early relative to much of the world, so we were building upon the oldest and most primitive system.
I love these little myths Americans tell themselves about doing things first. :)
The first general power station in the world is generally accepted to be in Godalming, Surrey, England. It was commissioned in 1881, and by 1882 8-10 households were connected up. The Holborn Viaduct electric light company started up the same year, and rapidly proceeded to where it had 1000 light bulbs on its supply.
However, I'm sorry to report that the French beat us to as to the first public use of electricity, in lighting up L'Avenue de l'Opera ten years earlier in 1878. The Germans (Siemens) were into the game pretty early too.
Edison's Pearl Street station in New York went into operation the same year as the Holborn Viaduct one in London (also an Edison owned plant), so America was electrifying at the same time as the rest of the world (those bits likely to electrify back in those days), not very early relative to the rest.
In 1887 an 800 kVA power plant was built in Deptford, East London, completed in 1891, it supplied central London over a 10 kV line, believed to be the first use of a high voltage transmission line.
Small, single household private supplies existed before this of course, I'm just talking about public utilities. In the case of private and early public supplies there was little standardisation, which is the point at which systems tend to build inertia.
So there's no special history that forced the US to live with existing standards because they started earlier than anyone else. Everybody was building on "early and primitive" systems at the same time.
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Thankfully, you can't put a fork or a skewer in ours..
No, but you can open the shutter with a screwdriver into the ground socket and insert stripped wires into the other two sockets. Removing the screwdriver will hold the two wires in place.
US code now requires "tamper resistant" receptacles in homes here too, they have shutters similar to the UK sockets. I don't like them personally, they cost as much as commercial grade stuff but are built like the cheap builder grade devices and sometimes it's hard to get some plugs to go in properly. It's easier to just not poke stuff into wall sockets. The live slot is small enough already that most metal objects like forks and coins and such won't go in anyway, stuff like hairpins and straightened paperclips, well a determined child will figure out how to open the shutters on UK receptacles anyway. I tend to view it as evolution in action. I've never known anyone who has known anyone who has had a kid electrocuted, it's pretty low on the list of household risks.
We just added a room to our house, and these 120 V "tamper-resistant" receptacles were installed (per code, I assume). They work fine with a three-prong plug, but double-insulated appliances usually have two-prong polarized plugs (neutral blade wider than line blade), and the shutters don't work well with them. To solve that problem, I use UL-listed circuit-breaker-protected three-prong plugged outlet strips, since the outlets are never in the right place anyway.
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We just added a room to our house, and these 120 V "tamper-resistant" receptacles were installed (per code, I assume). They work fine with a three-prong plug, but double-insulated appliances usually have two-prong polarized plugs (neutral blade wider than line blade), and the shutters don't work well with them. To solve that problem, I use UL-listed circuit-breaker-protected three-prong plugged outlet strips, since the outlets are never in the right place anyway.
Yes. It's a bit odd, and frustrating, to have a code that dictates that and still have two prong connectors everywhere. It was never an issue here, because the requirement for shutters came well after the move to 3 pin sockets that didn't physically accept any earlier two pin connectors. Shuttering was always a possibility, and by the time it was mandatory the necessary 3rd pin was a non-issue, it was already there on every cable. It's the norm here to have a 3 pin plug even on cables for double insulated equipment that doesn't actually use the redundant earth pin.
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Someone else has noted that it's normal to take the three phases and neutral down the whole street and tap different phases at different points for different building's supplies. It's quite possible that your next door neighbour is on a different phase - something to bear in mind if you're having a party in the garden and someone decides to throw an extension cord over the fence to power the disco lights from the neighbour's mains, while you power the music from your house's mains.
I once worked in a Lab where we discovered that adjacent workbenches were on different phases! :scared:
415V 3 phase ceiling drop to the end of each row of three benches and... :palm:
so what's the issue? each bench gets a phase and thus a fuse
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I've discussed all of this stuff at length with an engineer friend of mine in the UK and over the years we've come to the conclusion that there is no clear winner. The UK and various European systems have some advantages and the US system has other advantages, ultimately the important part is that all of these systems work, all of them are reasonably safe, all are capable of powering all the sorts of loads one is likely to have in their homes. I like the fact that there are still significant differences between them, in a world that is more and more globalized and homogenous. Very few of the classic brands of appliances are around anymore and stuff like a TV or food mixer is essentially identical and made in China no matter what part of the world you buy it in.
I like the UK plugs because they are chunky and sturdy, they hold the plug firmly in the socket even if it's a heavy old style wall wart and the plugs (that I've seen) are all right-angle so furniture can be placed close to the wall. The fused plugs are also a nice touch, it's one more protective device in the chain.
On the other hand the plugs are bulky, British power strips are massive things for the number of sockets on them compared to ours. The huge plugs are used even on light duty cords on compact and very low draw devices like mobile phone chargers. They also tend to land with the prongs pointed straight up if you leave them on the ground. Even though I have only a few devices with British plugs, I've still managed to step on one in my socks which does not feel good, though it's not as bad as TO3 transistors. :o
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The USA electrified very early relative to much of the world, so we were building upon the oldest and most primitive system.
I love these little myths Americans tell themselves about doing things first. :)
The first general power station in the world is generally accepted to be in Godalming, Surrey, England. It was commissioned in 1881, and by 1882 8-10 households were connected up. The Holborn Viaduct electric light company started up the same year, and rapidly proceeded to where it had 1000 light bulbs on its supply.
However, I'm sorry to report that the French beat us to as to the first public use of electricity, in lighting up L'Avenue de l'Opera ten years earlier in 1878. The Germans (Siemens) were into the game pretty early too.
Edison's Pearl Street station in New York went into operation the same year as the Holborn Viaduct one in London (also an Edison owned plant), so America was electrifying at the same time as the rest of the world (those bits likely to electrify back in those days), not very early relative to the rest.
In 1887 an 800 kVA power plant was built in Deptford, East London, completed in 1891, it supplied central London over a 10 kV line, believed to be the first use of a high voltage transmission line.
Small, single household private supplies existed before this of course, I'm just talking about public utilities. In the case of private and early public supplies there was little standardisation, which is the point at which systems tend to build inertia.
So there's no special history that forced the US to live with existing standards because they started earlier than anyone else. Everybody was building on "early and primitive" systems at the same time.
Well, I don't know then, I wasn't around back in those days but I'm sure there are historical reasons for it. Geographically the US is over 40 times the size of the UK, meaning things are far more spread out, there is far more infrastructure required per individual home, especially in the vast rural areas so it is far less cost effective to replace existing infrastructure. Maybe culturally we are also more resistant to change, I don't really know. Suffice to say electrical infrastructure we use today is largely compatible with what was being installed 100 years ago, the same ancient plugs will still fit in a the receptacles in a modern house, 100 year old light bulbs will still screw into modern sockets, the voltages are roughly the same now as they were then, and much of it was backward compatible with the DC systems that came even earlier. The lower voltage offered significant advantages for incandescent lighting which was the primary use of electricity in those days, later the proliferation of larger loads meant that 120V (or 110 or whatever it was at the time) was no longer adequate so the 240V split phase was introduced, maintaining compatibility with existing 120V loads.
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In my parents home even my bedroom had 3x16A 3-phase outlet ;D
Cool! :-+ Could someone post a pic of that? I'm familiar with industrial strength 3-phase outlets but never seen a domestic one here in Australia. I have 3-phase at home. Cost me an extra AUD$200 when the house got built in 1994. Instead of 1x100A I got 3x60A. That's what would fit in the underground conduit from the street to the house. Would have much rather had 3x100A of course. I was involved with 3-phase induction motor SCR soft starters / power savers at the time. Never actually got around to using it at home. Nowadays general power is on one phase, aircon and solar is on second and lighting on third. 240/415 here.
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Geographically the US is over 40 times the size of the UK, meaning things are far more spread out, there is far more infrastructure required per individual home, especially in the vast rural areas so it is far less cost effective to replace existing infrastructure.
It's always the size thing with you. Anyone would think you were compensating for something. :)
There are other big places too, Russia for instance, which certainly got into electricity back in the Tsarist days. That other places don't seem to have suffered the same inertia points to some difference. One thing might be that the US has traditionally leaned on private enterprise, where in other places there's been more state involvement. In the early days of electricity in the UK not only was it officially licensed, but there were clauses in the licenses that allowed local government to take over the operations if the electric company failed commercially - that points to a more centrally planned approach from the start. Perhaps some central planning is necessary for evolving the system and not merely building on what you've already paid for and own.
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In Russia, all apartment buildings have a three-phase connection. If the apartment has powerful equipment, such as an electric stove, it receives three-phase power. Detached houses have a 3-phase line next to each other and are connected to the phases in turn. Start all 3 phases only a matter of replacing the electricity meter and performing the work.
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This food fight about whether 120VAC either side of a centre tap is 1 or 2 phases; this is my take on it. The number of phases is equal to the number of different zero crossing points with respect to neutral. So you may have 6 different lines but only 3 different zero crossing moments so I say that's 3-phase.
With 2 sinewaves 90 deg apart you have 2 different zero crossing points so that's definitely 2-phase, but a single phase transformer with a centre tapped secondary does not produce two different zero crossings.
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It's always the size thing with you. Anyone would think you were compensating for something. :)
It's not a competition or superiority thing, it's an objectively true fact. The US (and Canada) are geographically huge with vast expanses of sparsely populated land with a huge percentage of the population clustered on the coasts. The scale of things is something that people in many European countries seem to be not fully aware of going by comments that come up over and over, and why would they be? There are any number of countries on the other side of the world that I have no idea how large they are, how the population is distributed or what reasons contributed to the design of their infrastructure.
I can only speculate on the reasons things were done the way they are, probably none of them that you'll be happy with other than "because we're stupid out here", maybe we just prioritize things differently. It is what it is, it evolved the way it did, and it's far too entrenched to change it now and not widely perceived as something that needs changing. We have so much crumbling ancient infrastructure that it would already cost trillions of dollars to replace all the stuff that really needs replacing, we're not going to replace stuff that works just because there are improvements that could be made today.
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This food fight about whether 120VAC either side of a centre tap is 1 or 2 phases; this is my take on it. The number of phases is equal to the number of different zero crossing points with respect to neutral. So you may have 6 different lines but only 3 different zero crossing moments so I say that's 3-phase.
With 2 sinewaves 90 deg apart you have 2 different zero crossing points so that's definitely 2-phase, but a single phase transformer with a centre tapped secondary does not produce 2-phase.
6 different lines? You'd never see such a thing. There are only two basic configurations here, and both start with a 3 phase medium voltage (usually 7200V/13500V). One of these configurations is 3 phase 120/208V using 3 transformers or a single 3 phase transformer delivering 3 live phases and neutral over 4 wires. The other is the typical residential distribution which takes one of the three 7200V (to neutral) phases and a transformer with a single center tapped 240V secondary and delivers this single phase 120V-Earth-120V to the house over 3 wires. There are never center tapped secondaries on a 3 phase system and there is still only one phase with the 120/240V arrangement. It's one or the other, 3 phase or single phase, there is no technological reason they couldn't supply 2 phase power but it isn't done.
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The USA electrified very early relative to much of the world, so we were building upon the oldest and most primitive system.
I love these little myths Americans tell themselves about doing things first. :)
The first general power station in the world is generally accepted to be in Godalming, Surrey, England. It was commissioned in 1881, and by 1882 8-10 households were connected up. The Holborn Viaduct electric light company started up the same year, and rapidly proceeded to where it had 1000 light bulbs on its supply.
However, I'm sorry to report that the French beat us to as to the first public use of electricity, in lighting up L'Avenue de l'Opera ten years earlier in 1878. The Germans (Siemens) were into the game pretty early too.
Edison's Pearl Street station in New York went into operation the same year as the Holborn Viaduct one in London (also an Edison owned plant), so America was electrifying at the same time as the rest of the world (those bits likely to electrify back in those days), not very early relative to the rest.
In 1887 an 800 kVA power plant was built in Deptford, East London, completed in 1891, it supplied central London over a 10 kV line, believed to be the first use of a high voltage transmission line.
Small, single household private supplies existed before this of course, I'm just talking about public utilities. In the case of private and early public supplies there was little standardisation, which is the point at which systems tend to build inertia.
So there's no special history that forced the US to live with existing standards because they started earlier than anyone else. Everybody was building on "early and primitive" systems at the same time.
Well, I don't know then, I wasn't around back in those days but I'm sure there are historical reasons for it. Geographically the US is over 40 times the size of the UK, meaning things are far more spread out, there is far more infrastructure required per individual home, especially in the vast rural areas so it is far less cost effective to replace existing infrastructure. Maybe culturally we are also more resistant to change, I don't really know. Suffice to say electrical infrastructure we use today is largely compatible with what was being installed 100 years ago, the same ancient plugs will still fit in a the receptacles in a modern house, 100 year old light bulbs will still screw into modern sockets, the voltages are roughly the same now as they were then, and much of it was backward compatible with the DC systems that came even earlier. The lower voltage offered significant advantages for incandescent lighting which was the primary use of electricity in those days, later the proliferation of larger loads meant that 120V (or 110 or whatever it was at the time) was no longer adequate so the 240V split phase was introduced, maintaining compatibility with existing 120V loads.
Here is a fun fact, a lot of Europe used to be 110V/120V but then everyone ended up going to 220V/240V that by now got standardized to 230V
In fact a firehouse here in Slovenia (Or was it Italy, land might have changed hands in that time) has a old lightbulb that has been continuously running for a ridiculus amount of years (Much like the oldest lightbulb in new york or what was it) and is so old that it initially ran off 110V. When they switched over to 220V they wanted the old bulb to keep going so they added another 110V bulb in series.
So we went down the same 110V path here in Europe but then noticed its not really that good of an idea, so we said fuck it, we are gonna do it properly and switched to 230/400V 3 phase running down whole streets. The efficiency of the new system is so much better that we don't even have polepigs. We simply plonk down one giant transformer at the beginning of the street, run the usual 20kV feed to it then run 230/400V straight down the street and connect houses directly to the pole. A single low voltage run down the street might have 30 to 100 houses connected to it. And one transformer might have 3 or 4 such runs coming off it. The wires running over the poles is not even that thick. We only have 2 kind of mains plugs, normal single phase ones for all appliances(even heavy ones) and standard 3 phase plug that is identical to ones used in industry but people have in homes.
So its not that America was first. They just never bothered to switch to the superior system and stuck to the outdated one... much like what they did with the metric system.
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There are never center tapped secondaries on a 3 phase system and there is still only one phase with the 120/240V arrangement. It's one or the other, 3 phase or single phase
(https://upload.wikimedia.org/wikipedia/commons/e/ea/CenterTappedTransformer.svg) (https://en.wikipedia.org/wiki/High-leg_delta)
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So we went down the same 110V path here in Europe but then noticed its not really that good of an idea, so we said fuck it, we are gonna do it properly and switched to 230/400V 3 phase running down whole streets. The efficiency of the new system is so much better that we don't even have polepigs. We simply plonk down one giant transformer at the beginning of the street, run the usual 20kV feed to it then run 230/400V straight down the street and connect houses directly to the pole. A single low voltage run down the street might have 30 to 100 houses connected to it. And one transformer might have 3 or 4 such runs coming off it. The wires running over the poles is not even that thick. We only have 2 kind of mains plugs, normal single phase ones for all appliances(even heavy ones) and standard 3 phase plug that is identical to ones used in industry but people have in homes.
So its not that America was first. They just never bothered to switch to the superior system and stuck to the outdated one... much like what they did with the metric system.
But as has been laid out already, we have 240V here too and have for many years. What makes single phase outdated and what true advantage does 3 phase offer for residences? Different does not mean inferior, and we've had 3 phase power in the US for a very long time, it has just never been commonly used in houses because it isn't necessary. Houses have few large induction motors, and simple, reliable 3 phase motors are the primary advantage of 3 phase. If I could upgrade my house to 3 phase service for the ridiculously low price of $100 I wouldn't bother. Why would I? What advantage would it bring over this "obsolete" system that I'm using? How do you sell it to a non-technical person who knows nothing about electricity?
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So we went down the same 110V path here in Europe but then noticed its not really that good of an idea, so we said fuck it, we are gonna do it properly and switched to 230/400V 3 phase running down whole streets. The efficiency of the new system is so much better that we don't even have polepigs. We simply plonk down one giant transformer at the beginning of the street, run the usual 20kV feed to it then run 230/400V straight down the street and connect houses directly to the pole. A single low voltage run down the street might have 30 to 100 houses connected to it. And one transformer might have 3 or 4 such runs coming off it. The wires running over the poles is not even that thick. We only have 2 kind of mains plugs, normal single phase ones for all appliances(even heavy ones) and standard 3 phase plug that is identical to ones used in industry but people have in homes.
So its not that America was first. They just never bothered to switch to the superior system and stuck to the outdated one... much like what they did with the metric system.
But as has been laid out already, we have 240V here too and have for many years. What makes single phase outdated and what true advantage does 3 phase offer for residences? Different does not mean inferior, and we've had 3 phase power in the US for a very long time, it has just never been commonly used in houses because it isn't necessary. Houses have few large induction motors, and simple, reliable 3 phase motors are the primary advantage of 3 phase. If I could upgrade my house to 3 phase service for the ridiculously low price of $100 I wouldn't bother. Why would I? What advantage would it bring over this "obsolete" system that I'm using? How do you sell it to a non-technical person who knows nothing about electricity?
With the current emerging trend of.. what's the popular term, microgeneration? Prosumering? Solar panels at scale, three-phase supplies make balancing far easier. Otherwise, it makes larger loads more practical (none of this giant aluminium trouble to run AC, no start and run caps..).
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So we went down the same 110V path here in Europe but then noticed its not really that good of an idea, so we said fuck it, we are gonna do it properly and switched to 230/400V 3 phase running down whole streets. The efficiency of the new system is so much better that we don't even have polepigs. We simply plonk down one giant transformer at the beginning of the street, run the usual 20kV feed to it then run 230/400V straight down the street and connect houses directly to the pole. A single low voltage run down the street might have 30 to 100 houses connected to it. And one transformer might have 3 or 4 such runs coming off it. The wires running over the poles is not even that thick. We only have 2 kind of mains plugs, normal single phase ones for all appliances(even heavy ones) and standard 3 phase plug that is identical to ones used in industry but people have in homes.
So its not that America was first. They just never bothered to switch to the superior system and stuck to the outdated one... much like what they did with the metric system.
But as has been laid out already, we have 240V here too and have for many years. What makes single phase outdated and what true advantage does 3 phase offer for residences? Different does not mean inferior, and we've had 3 phase power in the US for a very long time, it has just never been commonly used in houses because it isn't necessary. Houses have few large induction motors, and simple, reliable 3 phase motors are the primary advantage of 3 phase. If I could upgrade my house to 3 phase service for the ridiculously low price of $100 I wouldn't bother. Why would I? What advantage would it bring over this "obsolete" system that I'm using? How do you sell it to a non-technical person who knows nothing about electricity?
Alright here are the benifits:
1) 3 phase needs 4 wires to transfer 3x the power of single phase that needs 2 wires. So more power per wire
2) The 3 phases cancel out reducing the current in the neutral conductor to near zero, it only carries the current imbalance, this halves the conduction losses for a cable run.
3) Interphase voltage becomes 400V and so offering 4x the power over the same thickness of copper wire versus 110V
Notice i haven't even gotten to 3 phase motors, these are all just benefits in power distribution that lets us run 100+ houses directly from a single transformer rather than having pole pigs. But 3 phase motors have been significant in the old times before VFDs. We also don't have high population density here and a lot of land are farms, to any farm you go you will see machines with 3 phase motors everywhere due to there superior power and lower weight, 3 phase outlets on every corner to power them from.
And by the way Australia has 10 times lower population density than the US, guess what they use?
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And by the way Australia has 10 times lower population density than the US, guess what they use?
Very similar to us in NZ, 235VAC single phase and 415VAC 3 phase.
Not sure about their distribution networks but probably similar to ours:
Long range transmission backbone 400 KV DC
Medium range 220 KV AC
Some 110 KV
Regional feeders 33 KV
Terminal feeders 11 KV
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This food fight about whether 120VAC either side of a centre tap is 1 or 2 phases; this is my take on it. The number of phases is equal to the number of different zero crossing points with respect to neutral. So you may have 6 different lines but only 3 different zero crossing moments so I say that's 3-phase.
With 2 sinewaves 90 deg apart you have 2 different zero crossing points so that's definitely 2-phase, but a single phase transformer with a centre tapped secondary does not produce 2-phase.
6 different lines? You'd never see such a thing. There are only two basic configurations here, and both start with a 3 phase medium voltage (usually 7200V/13500V). One of these configurations is 3 phase 120/208V using 3 transformers or a single 3 phase transformer delivering 3 live phases and neutral over 4 wires. The other is the typical residential distribution which takes one of the three 7200V (to neutral) phases and a transformer with a single center tapped 240V secondary and delivers this single phase 120V-Earth-120V to the house over 3 wires. There are never center tapped secondaries on a 3 phase system and there is still only one phase with the 120/240V arrangement. It's one or the other, 3 phase or single phase, there is no technological reason they couldn't supply 2 phase power but it isn't done.
Oh, okay. My bad. I imagined a (sort of) star secondary with 6 ends and the centre neutral point grounded.
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There are never center tapped secondaries on a 3 phase system and there is still only one phase with the 120/240V arrangement. It's one or the other, 3 phase or single phase
(https://upload.wikimedia.org/wikipedia/commons/e/ea/CenterTappedTransformer.svg) (https://en.wikipedia.org/wiki/High-leg_delta)
Likely you could centre tap all three secondary windings and join them and take them down to ground. Wouldn't tolerate any unbalanced voltages though. Would make for lots of circulating currents. In that respect I suppose it would behave like a zigzag transformer. Is that topology ever used in practice?
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Whatever is grammatically most correct doesn't really matter, colloquially at least it is referred to as "single phase power" and technical people know that it is a single split phase.
Single phase... Sure... Split phase... Sure!
It is just most certainly not TWO PHASE! :)
Your ignorance is no reason for everyone else to change their language.
https://en.wikipedia.org/wiki/Two-phase_electric_power
They're rare, but they are called "two phase". Calling it "two phase" instead of "two phases" is no different than calling three phase "three phase" instead of "three phases", and no one seems to to be getting apoplectic about that.
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This food fight about whether 120VAC either side of a centre tap is 1 or 2 phases; this is my take on it. The number of phases is equal to the number of different zero crossing points with respect to neutral. So you may have 6 different lines but only 3 different zero crossing moments so I say that's 3-phase.
With 2 sinewaves 90 deg apart you have 2 different zero crossing points so that's definitely 2-phase, but a single phase transformer with a centre tapped secondary does not produce 2-phase.
6 different lines? You'd never see such a thing. There are only two basic configurations here, and both start with a 3 phase medium voltage (usually 7200V/13500V). One of these configurations is 3 phase 120/208V using 3 transformers or a single 3 phase transformer delivering 3 live phases and neutral over 4 wires. The other is the typical residential distribution which takes one of the three 7200V (to neutral) phases and a transformer with a single center tapped 240V secondary and delivers this single phase 120V-Earth-120V to the house over 3 wires. There are never center tapped secondaries on a 3 phase system and there is still only one phase with the 120/240V arrangement. It's one or the other, 3 phase or single phase, there is no technological reason they couldn't supply 2 phase power but it isn't done.
Oh, okay. My bad. I imagined a (sort of) star secondary with 6 ends and the centre neutral point grounded.
Actually this is one of those weird 230V delta transformers used in Norway.
Most other places will use distribution transformers that are wired for Delta on the high voltage input but wired for Y for the output so that it can have a neutral connection. But you could give it 120V center taps just the same.
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Whatever is grammatically most correct doesn't really matter, colloquially at least it is referred to as "single phase power" and technical people know that it is a single split phase.
Single phase... Sure... Split phase... Sure!
It is just most certainly not TWO PHASE! :)
Your ignorance is no reason for everyone else to change their language.
https://en.wikipedia.org/wiki/Two-phase_electric_power
You'll note that describes a true two-phase system with phase rotation. Split-phase, being 180 degrees out, has no rotation, which is why it is not equivalent to a two-phase system or two phases out of a three-phase system.
Actually this is one of those weird 230V delta transformers used in Norway.
Actually, it's one of those weird delta transformers used in the US to cover their mess of incompatible systems.
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Likely you could centre tap all three secondary windings and join them and take them down to ground.
That would be the equivalent of taking the end of each winding down to ground. Also known as a short circuit, or at these energy levels, an explosion.
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Actually, it's one of those weird delta transformers used in the US to cover their mess of incompatible systems.
I see... so then the 120V neutral is only a neutral for the 120V system while the 3 phase runs the Norway way of having no neutral.
Well at least this meant that the giant 3phase 5kW rack mount PSU i bought from the US on the cheap could run on our EU power by just connecting it across neutral and one phase (it didn't care about the 3rd phase missing).
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Actually, it's one of those weird delta transformers used in the US to cover their mess of incompatible systems.
I see... so then the 120V neutral is only a neutral for the 120V system while the 3 phase runs the Norway way of having no neutral.
Indeed. 120V loads use the neutral, 240V loads use any phase they like (or all three), and I believe 208V single-phase loads can be put across the high leg to the neutral, but I'm not sure why you'd bother as 208V only exists as a crappy compromise for having three-phase with 120V to neutral.
And on top of all that they've got 480V three-phase which isn't compatible with any of the rest, so there's a whole other category of 277V single-phase gear for that..
So to summarize: 120V single-phase, 208V single-phase, 208V three-phase, 240V single-phase, 240V three-phase, 277V single-phase, and 480V three-phase.
ROW, mostly: 240V single-phase, 415V three-phase. Your nominals may vary.
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Here is a fun fact, a lot of Europe used to be 110V/120V but then everyone ended up going to 220V/240V that by now got standardized to 230V
In fact a firehouse here in Slovenia (Or was it Italy, land might have changed hands in that time) has a old lightbulb that has been continuously running for a ridiculus amount of years (Much like the oldest lightbulb in new york or what was it) and is so old that it initially ran off 110V. When they switched over to 220V they wanted the old bulb to keep going so they added another 110V bulb in series.
So we went down the same 110V path here in Europe but then noticed its not really that good of an idea, so we said fuck it, we are gonna do it properly and switched to 230/400V 3 phase running down whole streets. The efficiency of the new system is so much better that we don't even have polepigs. We simply plonk down one giant transformer at the beginning of the street, run the usual 20kV feed to it then run 230/400V straight down the street and connect houses directly to the pole. A single low voltage run down the street might have 30 to 100 houses connected to it. And one transformer might have 3 or 4 such runs coming off it. The wires running over the poles is not even that thick. We only have 2 kind of mains plugs, normal single phase ones for all appliances(even heavy ones) and standard 3 phase plug that is identical to ones used in industry but people have in homes.
So its not that America was first. They just never bothered to switch to the superior system and stuck to the outdated one... much like what they did with the metric system.
Here's another fun fact, then: here in Brazil, we use both 127/220V standards (the good thing about standards is that there are so many to choose from, right? ;D), and we still call 127V "110" because that's what it used to be way back when. It can be 220V in one state and 127V in the next, or in some cases 220V in one city and 127V in the next... or you can get two phases from a 127/220V 3-phase system and have both in the same place. All sockets being exactly identical and it being up to you to know or indicate which one is which, of course.
My sister, who was living in a 127/220V state, blew up the power supply on her computer twice when she came over to visit (I live in a 220/380V state) because both times she forgot to flip the voltage switch. People who constantly travel between states with different voltage standards have to keep this sort of thing in mind, although it's less of a problem nowadays, with "voltage-agnostic" power supplies.
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Given two sinusoidal signals of amplitude \$V : A = V sin (\omega t + \phi_1) \text{ and } B = V sin (\omega t + \phi_2) \text { where } \phi_1 \neq \phi_2 \$ we would say that we were presented with two phases. The phase angles are different.
Why is this a special case when \$ \phi_1 \neq \phi_2 \text{ and } \phi_1 = 0, \phi_2 = \pi\$?
Vectors with exact opposite direction (180 degree phase difference), so that they are parallel to each other, cannot define a 2D space, only 1D space, and as a result, they cannot provide rotational vector, so such system cannot be used to produce a decent motor.
Or, looking it in different way, you can always create the inverted (180 deg shifted) waveform. A single-phase motor does this; some of the windings are wound in opposite direction, providing the 180 deg shifted pole of the pole pair. A full-bridge rectifier also does this.
Even a 3-phase motor does this; the minimum practical number of poles is 6 (for a 3-phase, 2 pole (= 1 pole pair) motor), and of each pole pair, one of the pairs is inverted.
So a single phase system easily allows generation of 0 deg and 180 deg vectors, wherever you need them, doing it earlier at the transformer adds no value compared to doing it at the motor. (Actual phases with phase shift not 0 or 180 deg can be generated by LC circuits, provided by run/start capacitors with single phase motors, and once the motor is running and storing momentum, a truly single-phase pulsating 1D vector can provide some torque with high ripple to keep it running.)
So a 180deg phase shifted second "phase" does not provide anything which already isn't available with a single phase wire. That's why we don't count it.
A "real" 2-phase system has the phase shift of 90 degrees; motors can then provide 0, 90, 180, 270 deg poles by choosing the winding direction per pole. This defines full 2D space and allows a true rotational torque vector. Such 2-phase systems are almost non-existing but we mentally use them to model 3-phase motors.
So yeah, we could define word "phase" in whatever way we want, for example, an imaginary 5-phase system could have the following phase shifts: 0 deg, 0 deg, 0 deg, 0 deg, 0 deg. But as a practical result, it would be identical to the single phase system.... just like systems that contain phases with +pi rad offset to already existing phases. These phases are not very useful. Hence, we talk about split-phase instead of 2-phase, and leave the term "2-phase" for the "true" 2-phase system with 90 deg phase shift.
Stepper motors are the most widely used case of 2-phase power system, although that may not be obvious to anyone looking at them first. When you microstep a "bipolar" stepper and look at the waveforms, you start to understand what's happening.
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In my parents home even my bedroom had 3x16A 3-phase outlet ;D
Cool! :-+ Could someone post a pic of that? I'm familiar with industrial strength 3-phase outlets but never seen a domestic one here in Australia. I have 3-phase at home. Cost me an extra AUD$200 when the house got built in 1994. Instead of 1x100A I got 3x60A. That's what would fit in the underground conduit from the street to the house. Would have much rather had 3x100A of course. I was involved with 3-phase induction motor SCR soft starters / power savers at the time. Never actually got around to using it at home. Nowadays general power is on one phase, aircon and solar is on second and lighting on third. 240/415 here.
It wasn't really any living room decoration, just normal 3x16A "industrial" outlet like this
https://www.ikh.fi/images/wwwkuvat/Tuotekuvat/CRX4021_S_1_web.jpg (https://www.ikh.fi/images/wwwkuvat/Tuotekuvat/CRX4021_S_1_web.jpg)
we have also this sort of 3-phase outlets if you want bit more refined looks:
(https://www.finnparttia.fi/WebRoot/vilkasfi01/Shops/2014102905/5491/4F19/5BBE/C592/A53D/0A28/1010/BF60/PR_516_U_5-napainen_16_A_uppoasennus_voimapistorasia_IP34_2520106.gif)
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Likely you could centre tap all three secondary windings and join them and take them down to ground.
That would be the equivalent of taking the end of each winding down to ground. Also known as a short circuit, or at these energy levels, an explosion.
Thinking about it further, yes, you are right. If A phase it at it's positive peak then B and C are equal and somewhat negative. Therefore the centre tap between B and C would be the same potential as B and C but the other two centre taps would be halfway between A and B or A and C. dzzzt!
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Yep we use those IEC standard 3 phase outlets in pretty much all of EU
Tho houses older than about 30 years over here still use the Yugoslavian 3 phase outlet. Its a pretty unique looking one compared to other sockets around the world.
(https://upload.wikimedia.org/wikipedia/commons/f/fc/3phase-plug-exYU1.png)
Its just simply the classical german Schuko socket that was already used for single phase being stretched out to give it room for the extra prongs. Most houses had at least one of these somewhere for cases when you needed to plug in something big like a big ass welder or saw.
This socket has one design flaw however. The spacing between the 3 phase prongs is the same as a normal single phase Schuko, but the body of those is too thick to fit in so you can't actually plug it in, but the compact thin itallian style EU plugs with no earth are compact enough to fit inside. When you do this you connect 400V into it and that means kaboom.
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How much it costs to get 3 phases service depends on the local installation. If they use the 3 phase system it can be cheap, if not it can be expensive because they need to run new wires and maybe transformers. So you have to live with the local system.
With underground cables the 3 phase system has some advantages (effectively higher voltage and less copper). With more pole mounted air isolated lines also for low power the split phase or 1 phase system has some advantage. In the US pole mounted wiring is a lot more common than in Europe. In Germany they are bringing also the 20 kV lines and now even new 380/400 kV underground.
3 Phase motors were also a big plus.
Old apartments can still have only 1 phase power, but this is rare and inconvenient for something like electric cooking. Usually it's still 3 phase for the house, but 1 phase per house. It makes the meters a little cheaper - though not much as 3 phase is the normal case.
For the 3 phase system there are also special 3 phase transformers, that combine all 3 phases with a 3 legged core. Using 3 separate transformers works, but uses slightly more material. It may be still an option for logistic reasons.
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A "real" 2-phase system has the phase shift of 90 degrees; motors can then provide 0, 90, 180, 270 deg poles by choosing the winding direction per pole. This defines full 2D space and allows a true rotational torque vector. Such 2-phase systems are almost non-existing but we mentally use them to model 3-phase motors.
I just checked what local universities teach EE students about multi-phase systems and found https://www.thm.de/iem/images/user/novender-978/gwds-19109.pdf. (https://www.thm.de/iem/images/user/novender-978/gwds-19109.pdf.) It's German - however, the diagram in section 3.19 shows a 2-phase system with the phases 180° apart. >:D
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A "real" 2-phase system has the phase shift of 90 degrees; motors can then provide 0, 90, 180, 270 deg poles by choosing the winding direction per pole. This defines full 2D space and allows a true rotational torque vector. Such 2-phase systems are almost non-existing but we mentally use them to model 3-phase motors.
I just checked what local universities teach EE students about multi-phase systems and found https://www.thm.de/iem/images/user/novender-978/gwds-19109.pdf. (https://www.thm.de/iem/images/user/novender-978/gwds-19109.pdf.) It's German - however, the diagram in section 3.19 shows a 2-phase system with the phases 180° apart. >:D
Nomenclature is arbitrary; understanding is more important. I think there is no law describing sanctions on calling split-phase system "2-phase". I recommend against doing that because it is highly confusing, while "split phase" instantly distincts the system from anything else and is easily googlable with good results. OTOH, I also recommend against assuming that someone talking about "2-phase" doesn't mean split-phase. True 2-phase (one which provides rotating 2D voltage or current vector which 1-phase or split-phase doesn't do) is such rarity, so better communicate explicitly and ask for clarification whenever someone talks about a 2-phase system.
I am also sure you'll be able to find many more errors, some much more problematic, in any number of university course materials; they are done by humans after all. I was originally hired at an Uni literally just to fix them.
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Given two sinusoidal signals of amplitude \$V : A = V sin (\omega t + \phi_1) \text{ and } B = V sin (\omega t + \phi_2) \text { where } \phi_1 \neq \phi_2 \$ we would say that we were presented with two phases. The phase angles are different.
Why is this a special case when \$ \phi_1 \neq \phi_2 \text{ and } \phi_1 = 0, \phi_2 = \pi\$?
Vectors with exact opposite direction (180 degree phase difference), so that they are parallel to each other, cannot define a 2D space, only 1D space, and as a result, they cannot provide rotational vector, so such system cannot be used to produce a decent motor.
Or, looking it in different way, you can always create the inverted (180 deg shifted) waveform. A single-phase motor does this; some of the windings are wound in opposite direction, providing the 180 deg shifted pole of the pole pair. A full-bridge rectifier also does this.
Even a 3-phase motor does this; the minimum practical number of poles is 6 (for a 3-phase, 2 pole (= 1 pole pair) motor), and of each pole pair, one of the pairs is inverted.
So a single phase system easily allows generation of 0 deg and 180 deg vectors, wherever you need them, doing it earlier at the transformer adds no value compared to doing it at the motor. (Actual phases with phase shift not 0 or 180 deg can be generated by LC circuits, provided by run/start capacitors with single phase motors, and once the motor is running and storing momentum, a truly single-phase pulsating 1D vector can provide some torque with high ripple to keep it running.)
So a 180deg phase shifted second "phase" does not provide anything which already isn't available with a single phase wire. That's why we don't count it.
A "real" 2-phase system has the phase shift of 90 degrees; motors can then provide 0, 90, 180, 270 deg poles by choosing the winding direction per pole. This defines full 2D space and allows a true rotational torque vector. Such 2-phase systems are almost non-existing but we mentally use them to model 3-phase motors.
So yeah, we could define word "phase" in whatever way we want, for example, an imaginary 5-phase system could have the following phase shifts: 0 deg, 0 deg, 0 deg, 0 deg, 0 deg. But as a practical result, it would be identical to the single phase system.... just like systems that contain phases with +pi rad offset to already existing phases. These phases are not very useful. Hence, we talk about split-phase instead of 2-phase, and leave the term "2-phase" for the "true" 2-phase system with 90 deg phase shift.
Stepper motors are the most widely used case of 2-phase power system, although that may not be obvious to anyone looking at them first. When you microstep a "bipolar" stepper and look at the waveforms, you start to understand what's happening.
Ah, someone who missed the >:D. I was just having a poke at the prescriptivists who were bring a little bit silly about arguing over saying two phases or split phases. Looks like someone took the bait. I was impressed by the number of people who were smart enough not to fall for it.
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Ah, someone who missed the >:D.
Actually I didn't miss it! I just wanted to provide the explanation nevertheless, if not for you, for the others looking at this thread, because this is something worth giving a thought about; your question why 180 deg shift is different, is a really good one. Good to hear confirmation that we don't have to run in circles with this, not that I would have participated in 2nd round of trolling, anyway.
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20 years ago I used to wish I had 3 phase, but now I don't care. When I want to run a 3 phase motor I run it on a VFD, and I'd do the same even if I had 3 phase into the house just due to all the other features it gives you. I have no other use for 3 phase power.
1) Let's say you have 220V/240VAC 60 Hz from the grid, can your VFD get a 220V/240VAC 50Hzon the output?
I think, the answer is yes
2) Let's say you have 220V/240VAC 60 Hz from the grid, can your VFD get a 380VAC (1 or 2 or 3 phases) on the output?
I think, the answer is no
So if I have a 220VAC 50 HZ motor from EU I can run it in US, but if I have a 380VAC equipment it will be a circus acrobatic jazz to get it working in the US.
right?
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20 years ago I used to wish I had 3 phase, but now I don't care. When I want to run a 3 phase motor I run it on a VFD, and I'd do the same even if I had 3 phase into the house just due to all the other features it gives you. I have no other use for 3 phase power.
1) Let's say you have 220V/240VAC 60 Hz from the grid, can your VFD get a 220V/240VAC 50Hzon the output?
I think, the answer is yes
2) Let's say you have 220V/240VAC 60 Hz from the grid, can your VFD get a 380VAC (1 or 2 or 3 phases) on the output?
I think, the answer is no
So if I have a 220VAC 50 HZ motor from EU I can run it in US, but if I have a 380VAC equipment it will be a circus acrobatic jazz to get it working in the US.
right?
A VFD just takes whatever supply it has and rectifies it to DC. Then it typically uses MOSFET half-bridges to PWM that DC into whatever AC waveforms you want/need.
If the required peak voltage of your output waveform is higher than the peak voltage of the input AC supply then instead of a simple rectifier bridge to get your intermediate DC bus you have to use a boost convertor to get there. Of course it is possible to combine active input rectification and a boost convertor as a single stage, and VFDs that also do power factor correction do this anyway.
So a VFD using simple rectification can produce any arbitrary frequency output, with a peak voltage up to the peak voltage of the incoming mains. Only VFDs that include a boost stage can produce a higher output voltage than input voltage.
Needless to say that in any case voltage-wise, you can have as many output phases as you like, you just need an output half-bridge for each phase.
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Oh I did not know about the VFD with boost.. interesting piece of kit.
What are good brand VFD? I need maybe need a VFD from 240VAC 60HZ to 240 50HZ, 3KW.
BTW, do I really need the 50Hz or VFD? I mean a 50Hz motor will get in trouble if I feed it with 60Hz?
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I shot some video yesterday, will try to edit up a couple things to post. :)
I'm headed back over to the car wash now to change out that broken pilot assembly on the west 1,200,000 BTU wash-water boiler and hopefully shoot a bit more stuff I should have thought to mention about the 3-phase electrical and where I want to upgrade to VFDs, so I can try to edit it in...
I suppose you won't know what I'm talking about on that until you see some of the video... :D
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Oh I did not know about the VFD with boost.. interesting piece of kit.
What are good brand VFD? I need maybe need a VFD from 240VAC 60HZ to 240 50HZ, 3KW.
BTW, do I really need the 50Hz or VFD? I mean a 50Hz motor will get in trouble if I feed it with 60Hz?
One of the major advantages of using a VFD is the speed control, so the input frequency that the motor is expecting doesn't really matter, you can generate whatever you want. That's the beauty of a VFD and the whole point!
This all ties in with the things I'm talking about at the car wash, I would like to soft-start the 3HP 3-phase (208-240V motors) high pressure pumps. Well I'd like to soft-start pretty much everything there that is a big 3-phase motor.
I'll try to edit up some video clips later today if I can find the time!
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I mean a 50Hz motor will get in trouble if I feed it with 60Hz?
Many motors will run fine on the "wrong" frequency (won't burn up or something) but the speed will be different due to the different input frequency. Many motors do explicitly state on the rating plate the speeds that they will run on 50 Hz vs 60 Hz....
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One of the major advantages of using a VFD is the speed control, so the input frequency that the motor is expecting doesn't really matter, you can generate whatever you want. That's the beauty of a VFD and the whole point!
And of course with the ascendency of VFDs and active motor control in general people tend to have stopped thinking in terms of fixed speed synchronous motors that are designed with a specific mains frequency in mind and more in terms of a general synchronous motor (usually a permanent magnet motor until you start getting really big) that can operate across a significant range of frequencies and speeds.
Of course there are a lot of fixed speed synchronous direct mains connected motors out there, but as they come up for replacement it's highly likely that the replacement is going to involve active control (aka a VFD).
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6 different lines? You'd never see such a thing.
For rectifier transformers, 6 phases are needed above about 1500 kW to meet harmonic content standards.
Above about 3000 kW, 12 phases are needed.
6 phases are obtained on the secondaries of one tranformer with 3 phase input.
12 phases are usually obtained by using two transformers, each with a zig-zag 3 phase primary. +/- 7.5 degrees.
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It should just be DC all the way, baby >:D.
Just kidding, the safety issues alone would give me nightmares.
I have 200A, 240VAC single phase in the NE US. Most of my area started at 60A through the 1950s, 100A in the 1960s, and now 200A seems to be the standard, since you need to power those air conditioners. It cost me about $1000 USD to upgrade from 100A to 200A, and this included the cable from the power head to the breaker box, a new, much larger breaker box, and installation.
There are a lot of advantages to 3-phase in industry, but in the US, the rediential single phase system is in place, and the main reason for three phase, motors, is rapidly going away due to the low cost of VFDs. These provide huge advantages to motors (variable speed, all kinds of protection, etc.). And many appliances have already moved to this combination (BLDC is essentially the same system) because of these benefits. My clothes washer, dishwasher, fridge, and AC units all have VFDs of some sort. They can be really, really cheap as part of a custom appliance control system, and they let you use a cheaper motor. I recently replaced a 16 year old clothes washer, and the old one had a VFD, which still worked (the failure was an aluminum bearing strut).
Since the advent of three-phase VFDs, I quit thinking about 3-phase for my house.
John
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Since the advent of three-phase VFDs, I quit thinking about 3-phase for my house.
Yup.... Pretty much the only reason you would have ever wanted to have real three phase at home would be to run some large motor, but now a VFD makes that easy anyway, regardless of the input.
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Yep 50Hz or 60Hz doesn't really matter for a motor. It simply runs a bit faster on 60Hz . You can even use a VFD to put 100Hz into such a motor to get it going even faster, but the torque becomes limited because there is not enough voltage to push as much current trough the motor.
As for a VFD shifting voltage up, that is not a problem. Any big VFD needs to have a PFC input in order to not polute the mains input with tons of harmonics. This active PFC is simply a rectifier followed by a boost converter that boosts the lower parts of the sinewave up in order to let it use power troughout the entire sine wave cycle rather than just at the sine peaks that a typical rectifier and capacitor would do. To get more voltage on the DC bus this boost converter simply needs to be designed to boost it up even higher.
BLDC motors are indeed the best kind of motor design in terms of performance, the permanent magnets bringing there own field in them make the work of the stators electromagnets easier and so give a more powerful motor in a smaller and lighter form factor. The VFDs required to run this versus 3 phase async is pretty much the same apart from slight algorythem changes. But there will still be cases where they just don't care about any soft start or fancy speed control, the sort of stuff where they just want a blower fan to push some air when they flip a switch, for that the simple and reliable asynchronus motor is just fine. Tesla knew what he was doing.
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I fully agree, a single phase would work fine for most households. The difference is where the loads of the 3-phase grid are balanced. In some countries the loads are balanced via the pole transformers or flats/homes, while in other countries the loads are balanced in each flat's distribution panel.
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Reason I am asking is maybe I will move to US, and I have all my tools/equipment from EU I want to use in USA.
The plan is to rewire the US home taking the 240VAC 60HZ into a 40A European RCD on a separate EU panel and install some german schuko plugs in my future home.
VFD is nice but I think I will not bother to power my EU stuff.
I personally like much more the european 240VAC plugs and grid network components.
Nothing can beat a IEC 60309.. The blue ones, I love them... and I will install somel in my future USA garage for sure.
The US plugs are poorly designed in my eyes.
PS: I lived already in USA and one day the lights were acting funny, I measured the main and I was getting 230VAC in the 110VAC ones. Probably some street trafo went kaboom...
Some little switching PSUs melted but thank God nothing big was on during the grid malfunction.
My home will have something if vmain> 140VAC or so then cut the power, thank you and goodbye.
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Since the advent of three-phase VFDs, I quit thinking about 3-phase for my house.
Yup.... Pretty much the only reason you would have ever wanted to have real three phase at home would be to run some large motor, but now a VFD makes that easy anyway, regardless of the input.
for a VFD it can also be an advantage with three phases input making it easier to rectify to the DC bus voltage
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For rectifier transformers, 6 phases are needed above about 1500 kW to meet harmonic content standards.
Above about 3000 kW, 12 phases are needed.
Wait... What?!
I thought we were mostly talking about the need (or want) for residential three-phase...
If you need 3 megawatts to your garage, what kind of time machine are you developing in there? :o
Do tell! I may find your ideas intriguing and wish to subscribe to your newsletter!
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For rectifier transformers, 6 phases are needed above about 1500 kW to meet harmonic content standards.
Above about 3000 kW, 12 phases are needed.
Wait... What?!
I thought we were mostly talking about the need (or want) for residential three-phase...
If you need 3 megawatts to your garage, what kind of time machine are you developing in there? :o
Do tell! I may find your ideas intriguing and wish to subscribe to your newsletter!
I am sorry that I seem to have offended you, but if you read the post of drussell that I snipped ( perhaps too much), you will see that he was referring to 7kV and 13 kV distribution which is right at the level where the transformers I mentioned, are used.
And the reason the 6 phase etc is used, is that it is a practical way of keeping distortion low on those distribution levels.
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For rectifier transformers, 6 phases are needed above about 1500 kW to meet harmonic content standards.
Above about 3000 kW, 12 phases are needed.
Wait... What?!
I thought we were mostly talking about the need (or want) for residential three-phase...
If you need 3 megawatts to your garage, what kind of time machine are you developing in there? :o
Do tell! I may find your ideas intriguing and wish to subscribe to your newsletter!
I am sorry that I seem to have offended you, but if you read the post of drussell that I snipped ( perhaps too much), you will see that he was referring to 7kV and 13 kV distribution which is right at the level where the transformers I mentioned, are used.
And the reason the 6 phase etc is used, is that it is a practical way of keeping distortion low on those distribution levels.
Heh... not offended in any way, of course... I just should have added a ;) at the end. Haha
't'was tongue-in-cheek... :D
Darn, so you're not developing a time machine? Awwww.... :D
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All OK,
I think has been a good thread and interesting to read the comments from a diverse group of experiences.
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It has a lot to do with zoning of your area and the infrastructure that is in place. Residential areas don't need 3 phase so it's not part of the infrastructure. Why add that extra cost to a zone if 3 phase probably won't be used. I don't know which part of the country your in but there are also City bylaws and Provincial laws that prevent industrial activity in residential zones. If you live outside a city limit then you should have no problem getting 3 phase installed . Or if you live in an older community like mine that has 3 phase from past industrial services . But even here it's slower being removed because it's not used anymore.
Where i have lived, 3-phase is on the power poles, with periodic transformers converting one of the phases to isolated split phase, but zoning regulation forbid providing 3-phase to homes specifically to prevent the use of "industrial" machinery in residential areas.
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Where i have lived, 3-phase is on the power poles, with periodic transformers converting one of the phases to isolated split phase, but zoning regulation forbid providing 3-phase to homes specifically to prevent the use of "industrial" machinery in residential areas.
Then the guy with a rotary converter has the last laugh at the paper pushing idiots.
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Where i have lived, 3-phase is on the power poles, with periodic transformers converting one of the phases to isolated split phase, but zoning regulation forbid providing 3-phase to homes specifically to prevent the use of "industrial" machinery in residential areas.
Then the guy with a rotary converter has the last laugh at the paper pushing idiots.
need some way to turn that pesky electricity into noise and heat ;)
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Where i have lived, 3-phase is on the power poles, with periodic transformers converting one of the phases to isolated split phase, but zoning regulation forbid providing 3-phase to homes specifically to prevent the use of "industrial" machinery in residential areas.
strange attitude. in Switzerland the entire low-voltage network delivers 3ph to the houses; even the 400 year old stone hut in the southern alps where I lived over 10 years had 3ph fused at 25A each; I was glad to have it since it allowed me to use a 3ph wood chopper without the need to rebuild or a VFD. Most higher power household appliances like stoves or wash driers run on 380V here.
although I didn't wire up my lab with 3ph; I had it in my old QTH, but actually never really used it.
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Where i have lived, 3-phase is on the power poles, with periodic transformers converting one of the phases to isolated split phase, but zoning regulation forbid providing 3-phase to homes specifically to prevent the use of "industrial" machinery in residential areas.
Then the guy with a rotary converter has the last laugh at the paper pushing idiots.
He only laughs up to the point where a neighbor files a complaint and the paper pushing idiots start harassing him for "running a business" at his home. And somewhere behind those paper pushing idiots are more idiots with guns.
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Where i have lived, 3-phase is on the power poles, with periodic transformers converting one of the phases to isolated split phase, but zoning regulation forbid providing 3-phase to homes specifically to prevent the use of "industrial" machinery in residential areas.
strange attitude. in Switzerland the entire low-voltage network delivers 3ph to the houses; even the 400 year old stone hut in the southern alps where I lived over 10 years had 3ph fused at 25A each; I was glad to have it since it allowed me to use a 3ph wood chopper without the need to rebuild or a VFD. Most higher power household appliances like stoves or wash driers run on 380V here.
although I didn't wire up my lab with 3ph; I had it in my old QTH, but actually never really used it.
Well if you're looking for logic in politics you are bound to be disappointed. It's very common to have people legislating on things they know little or nothing about. The person or group who decided to ban 3 phase to residential units in that area probably had no idea that rotary converters or VFDs existed and thought that the proposal was a perfectly reasonable way to prevent something viewed as undesirable. A knowledgeable person is just going to be frustrated trying to make sense of it.
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Reason I am asking is maybe I will move to US, and I have all my tools/equipment from EU I want to use in USA.
The plan is to rewire the US home taking the 240VAC 60HZ into a 40A European RCD on a separate EU panel and install some german schuko plugs in my future home.
VFD is nice but I think I will not bother to power my EU stuff.
I personally like much more the european 240VAC plugs and grid network components.
Nothing can beat a IEC 60309.. The blue ones, I love them... and I will install somel in my future USA garage for sure.
The US plugs are poorly designed in my eyes.
PS: I lived already in USA and one day the lights were acting funny, I measured the main and I was getting 230VAC in the 110VAC ones. Probably some street trafo went kaboom...
Some little switching PSU melted but thank God nothing big was on during the grip malfunction.
My home will have something if vmain> 140VAC or so then cut the power, thank you and goodbye.
I don't think it's legal to do what you propose, however I don't think anyone is likely to come hassle you about it either. I've thought it would be amusing to install a UK socket in my den/office/project room fed by a 240V 50Hz inverter in the garage but instead I've just set up something on the bench when I need 50Hz power for something.
I suspect what happened was you lost the neutral in the panel resulting in the two legs of 120V branch circuits being in series. It happened to my grandmother's house once when a direct lightning strike to the pole in her yard vaporized the neutral conductor in the meter base which was out on that pole. Occasionally it happens due to damaged or improperly installed connections in the breaker panel but it's rare. If you have decent quality gear that is properly installed and not abused it's a very rare event.
When I was a kid my friend's house had a bunch of electrical stuff damaged after a high voltage transmission line fell on a lower voltage line and caused the voltage to go way up, probably limited by saturation of the transformer feeding his house. I don't know the exact circumstances around that but it's the only time I've heard of such a thing happening.
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Yep fallen off neutral can cause that exessive voltage.
Similar thing happens in 3 phase if the neutral gets disconnected for some reason. The load is never quite ballanced when a bunch of single phase loads are hanging off it, so when neutral falls away that neutral point gets dragged off towards the most loaded phase, causing a lot more voltage to show up on the other two phases. Its perhaps not as bad as on split phase since worst case you can get is 400V, so not quite double the normal voltage, but its still plenty enugh to fry stuff, specialy power supplies.
As for running a VFD around the house they are not really ment to do that since they also have some current feedback and the output waveforms can be quite a PWM mess. But you can certainly buy a huge beefy 3 phase UPS and use it for that.
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something on the bench when I need 50Hz power for something.
Some ghetto gangs use a 50Hz signal generator into an audio amplifier. the speaker output are then connected to some secondaty trafo. Finally the DUT is then feeded by the trafo primary.
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something on the bench when I need 50Hz power for something.
Some ghetto gangs use a 50Hz signal generator into an audio amplifier. the speaker output are then connected to some secondaty trafo. Finally the DUT is then feeded by the trafo primary.
I've seen it done. I came into possession of an old California Instruments "Invertron" which is essentially a big linear amplifier driving an output transformer which will deliver 500VA at up to 300V at a frequency from 40Hz to 5kHz. It's a boatanchor and has a very noisy fan but it does the job. I've also got a modern true sine inverter board that I need to finish building into a completed unit at some point.
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Reason I am asking is maybe I will move to US, and I have all my tools/equipment from EU I want to use in USA.
The plan is to rewire the US home taking the 240VAC 60HZ into a 40A European RCD on a separate EU panel and install some german schuko plugs in my future home.
VFD is nice but I think I will not bother to power my EU stuff.
I personally like much more the european 240VAC plugs and grid network components.
Nothing can beat a IEC 60309.. The blue ones, I love them... and I will install somel in my future USA garage for sure.
The US plugs are poorly designed in my eyes.
PS: I lived already in USA and one day the lights were acting funny, I measured the main and I was getting 230VAC in the 110VAC ones. Probably some street trafo went kaboom...
Some little switching PSU melted but thank God nothing big was on during the grip malfunction.
My home will have something if vmain> 140VAC or so then cut the power, thank you and goodbye.
I don't think it's legal to do what you propose, however I don't think anyone is likely to come hassle you about it either. I've thought it would be amusing to install a UK socket in my den/office/project room fed by a 240V 50Hz inverter in the garage but instead I've just set up something on the bench when I need 50Hz power for something.
Definitely not code to rewire in this way throughout the house. Why does it matter? If you ever have a fire or any electrical problem, your insurance companies will not pay you anything, and if someone gets hurt or worse, you will be sued within an inch of your life. Or, if you ever plan to sell your house, the modified wiring system will be a huge liability.
You may be able to have a separate wiring systems as long as it can somehow be considered "not permanent", and have it plug into a 240V outlet in the garage. We do have 240V outlets and wiring that meets code, but they are not European.
Unless you just plan to live in the boonies and you don't care about any of this stuff. Then you can just do whatever you want.
John
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I can't argue with your desire to use your Euro equipment. But why swim upstream? While you and many others have no respect for the US standard 110V 15A and 20A outlets, there are other options which comply with local codes and meet your needs and might even get your approval. Buying or building a set of inline adapters so you don't have to change the power cords on your equipment would leave your home compliant with local codes, much easier to sell and probably not any more expensive than the wiring job you propose.
It would be just as pointless for an American (comfortable with the standards he was used to) to rewire a European home to American standards.
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Usually 3 phase is delivered to a substation that splits the single phases to different streets. It does not make economic sense to put all 3 phases down every street just in case one person wants it as it adds to the cabling required. No point in the OP going frantic. You want an industrial power supply? move to an industrial location.
I think you'll find that pretty much all of UK residential streets have a 3-phase supply running along them, whether they're above ground or buried. The odd exception might be a tiny rural group of houses that only justifies a single phase pole mounted transformer.
Buried street cables are 3 phase (and neutral outer sheath) with 2-3 adjacent houses tapped off each phase to balance the load. Ours is on the yellow phase (old colour coding convention).
Over the years there’s been a few power cuts where I live (including one where the pavement blew up outside neighbours house) and in all but the last one, the whole street was out.
Last one was funny to see, it happened early evening, when dark.
My house, neighbour to the right had no power, neighbour to the left had power. Shop 30 yards away had to close as it lost 1/2 its power. And looking down the street, it was an unusual sight (for me) seeing a few houses with power then a few without etc
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Last one was funny to see, it happened early evening, when dark.
My house, neighbour to the right had no power, neighbour to the left had power. Shop 30 yards away had to close as it lost 1/2 its power. And looking down the street, it was an unusual sight (for me) seeing a few houses with power then a few without etc
These are not unusual when one phase of the HV supply drops out and the effect on the end user depends entirely on which phase feeds them when fed with a single phase supply.
Lights dim greatly and can go out completely if additional loads are added to the mains.
In the past when confused about what was happening the Fluke measured from ~70-120VAC whereas we're normally 235VAC. Mad panic ensues as we rush around turning OFF any load that could possibly be damaged by such low voltages and special attention is paid to any 3ph loads fed from our other 3ph supply that might automatically turn ON while only 2 phases are active. :scared:
Phase failure protection relays have now been added to such loads. ;)
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I had a tree limb take down the line from the power line to the house a few years ago which only resulted in breaking the neutral. Since it was going to take a few days for the power company to repair, I used my massive 240 volt AC phase splitter to regenerate the neutral connection for the whole house preserving balance between the 120 volt AC phases.
I tried including a picture but the forum is not accepting it.
"Your attachment has failed security checks and cannot be uploaded. Please consult the forum administrator."
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I had a tree limb take down the line from the power line to the house a few years ago which only resulted in breaking the neutral. Since it was going to take a few days for the power company to repair, I used my massive 240 volt AC phase splitter to regenerate the neutral connection for the whole house preserving balance between the 120 volt AC phases.
I tried including a picture but the forum is not accepting it.
"Your attachment has failed security checks and cannot be uploaded. Please consult the forum administrator."
This problem has hit a few people. The administrators don't know what the problem is. Pasting pictures in a .pdf document is one way around it.
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Usually 3 phase is delivered to a substation that splits the single phases to different streets. It does not make economic sense to put all 3 phases down every street just in case one person wants it as it adds to the cabling required. No point in the OP going frantic. You want an industrial power supply? move to an industrial location.
That is not unfortunately the full truth.
Calculate how much power you can transfer with a single phase using amount X of copper. Then calculate same, using the same amount X of copper split for three phases.
As what you said, is a mathematically proven nonsense. Also, having separate loads on each phase create load imbalances and a lot more issues and stupid inconveniences.
I don't understand what you're getting at there.... Could you elaborate a little, please?
Three phase distribution can move 2-times more power per same amount of copper in the lines.
With that american split-phase thing, it is even more times.
That's why it's more then enough for a EUropean houshold to have just a 3x20 or 3x25A breaker panel. Even that is hell of a lot. (17 kW).
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your insurance companies will not pay you anything, and if someone gets hurt or worse, you will be sued within an inch of your life. Or, if you ever plan to sell your house, the modified wiring system will be a huge liability.
I was expecting that in the first response, finally...
I know. When I was in US I had already done that. It would be a smart thing, so I will turn it into normal US home in 5 minutes.
Regarding safety it will be more safe than a normal US home, trust me.
As long I am safe, I will sleep well at night.
You should see the moving company last time when I was going back to EU. The last thing they packed was the screw driver after I relocated the wires in the main grid panel.
It was funny.
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Note that the complete analysis of how AC induction motor works fundamentally changes if driven off mains vs. with VFD. The whole point of the VFD is to monitor the motor state and work it in optimal conditions (simplified: with optimal slip). When run off mains, running the motor in (nearly) optimal conditions happens only in very lucky (or very well engineered!) cases, namely if the load happens to be just right for the motor and the load torque is not varying (except for very short times, during which we just decide it doesn't matter).
Real-world off-mains usage of 3-phase motors requires special considerations like soft-starting, delta-wye switching, power factor correction etc. etc., which all become off-topic when driving with VFD. This is not even to mention mechanical gearboxes, gear switching, clutches, belts and whatnot used to deliver torque far from the optimal rpm (synchronous frequency minus slip).
Off-mains motors may be even designed to provide somewhat better performance far below the optimal slip, compromising the efficiency at optimal slip. Such compromised motor would be a wasted effort when driven on VFD.
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Yep 50Hz or 60Hz doesn't really matter for a motor.
Even for a single phase motor with a starting cap? I mean a 1/j2pi*f*C cap@50Hz != cap@60Hz , or event the magnetic flux in the motor windings will be different in amplitude, not just in frequency.
Or the difference is not noticeable in real life? Sorry if it was a stupid question, I just have some university memories about motors.
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What is worse, high or low voltage?
Can't remember what regular gadgets have most but least is many times under 200.
Here voltage is already lifted twice but can't remember any fuss around them.
Only argument I can remember was around 0-class and schuko wall outlets.
Here original single phase contract is probably around 50 years old minimum.
That is also truly single, means phase to ground and probably 20A or so.
Disadvantage here can be the length of a user line.
Rural last drop has many times been one drop only from middle voltage grid so distribution point can be guite far.
Not very optimal if you are a summer cottager after say a dairy farm or two.
On the other hand, around here summer nights are short and solar panels affordable.
What about a stove clock then.
With 3-phases the clock can stay one no matter how lightning is flicking the lights.
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Yep 50Hz or 60Hz doesn't really matter for a motor.
Even for a single phase motor with a starting cap? I mean a 1/j2pi*f*C cap@50Hz != cap@60Hz , or event the magnetic flux in the motor windings will be different in amplitude, not just in frequency.
Or the difference is not noticeable in real life? Sorry if it was a stupid question, I just have some university memories about motors.
Technically yes it does change the shift, but the motors don't care that much about it being spot on, it just needs something in the ballpark of the correct phase shift so that it can create torque at standstill so that it can start up. The capacitor contributes very little to the total torque once the motor is running at nominal speed. In fact some single phase motors use it only for start and then disconnect it using a centrifugal switch, this lets them under-spec the starting windings with thinner copper since they only need to work for a few seconds, they can put the extra copper to better use by giving it thicker main windings as those produce the power, at the same time optimizing the starting windings to give more torque at a standstill. Remember the phase shift on the capacitor can also change as the real and reactive power move around on the motor winding under different running conditions.
This is also why the starting torque on single phase async motors is so poor. They like having easy to start loads like fans or saws. The 3 phase async motor is quite a bit better at starting torque since it has those extra proper full power phases at its disposal, but at the same time this creates startup problems on the power supply side since async motors are horribly efficient once slip gets too high, so when they try to produce so much torque they draw an insane amount of current. This is typically solved by a delta/star starting switch since running in star makes the motor see less voltage so it draws less current, once its up to speed its switched to delta for full power at full voltage. Its a pretty cheap solution since motors with a manual on/off switch can simply replace it with a 3 position switch that goes OFF/Star/Delta and the operator simply leaves it in Star for a few seconds before switching to Delta. Power factor correction and such is not a big issue, a factory simply has a centralized power factor correction bank at the transformer that switches in caps across the supply to correct the inductive reactive power from motors in the whole factory. The speed of the motor is not a problem as long as you always need it to run at the same speed, just simply chose a motor with the correct number of poles for the speed you need, more poles, closer together the electromagnets are so 50Hz takes longer to get around so the motor spins slower and produces more torque. Over-specing a 3 phase motor is not that bad either, it still runs pretty efficient with a too light load, its efficiency just drops off a cliff once you overload it (causing the slip to get too big, causing speed to drop, slip increase even more...etc)
But yes the modern solution to all that is simply a VFD. Just flick a switch and the VFD will slowly bring up the voltage and frequency to gently soft start the motor and give it even more torque since the frequency is matched to the speed so that its operating in an efficient regime all trough the startup ramp. Also the sort of machines that big motors run in the home shop tend to benefit from speed control. Having a simple speed dial on your mill, lathe, drillpress, grinder, bandsaw etc... is nice to have.
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Three phase distribution can move 2-times more power per same amount of copper in the lines.
Three phase four conductor is generally more Cu efficient and at the same time it has sqrt3 higher voltage so it is a bit like comparing apples and oranges as different ratings of cables are needed. And same rating cable with 230V withstands more abuse than with 400V. But I must agree, sheath does not count as Cu cost.
That was cable-wise. As for the safety-wise, three phase is a compromise in between high'er power and low'er voltage. You can have both from four wires. That is why three phase is a sweet spot. Had you increased single phase to 400V, Cu-wise this would have been a tad cheaper than 4 conductor three phase 230V/400V.
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Thanks Berni, I appreciate your patience to write down this good explanation.
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Three phase distribution can move 2-times more power per same amount of copper in the lines.
Three phase four conductor is generally more Cu efficient and at the same time it has sqrt3 higher voltage so it is a bit like comparing apples and oranges as different ratings of cables are needed. And same rating cable with 230V withstands more abuse than with 400V. But I must agree, sheath does not count as Cu cost.
That was cable-wise. As for the safety-wise, three phase is a compromise in between high'er power and low'er voltage. You can have both from four wires. That is why three phase is a sweet spot. Had you increased single phase to 400V, Cu-wise this would have been a tad cheaper than 4 conductor three phase 230V/400V.
Cable rating is exactly the same 300/500V, which means Uo/U (against ground/against each other). Same rated cables used everywhere, even for single phase stuff.
Hence I find your complaint void. No difference buying a cable for single phase, or three phase application - with the exception of some household flexible cords, the thin stuff, that is just 300/300 rated. Some "high power" low voltage cables are rated 500/700V, because at times, we use even higher voltages than 230/400V. For example, if I am not mistaken, mines run at 500V 3ph ac and some application use even higher voltages such as 690V.
This is standardized across the whole EU. Look for H03, H05 H07 type of wires/cables. I think it is in IEC 60227-3.
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Usually 3 phase is delivered to a substation that splits the single phases to different streets. It does not make economic sense to put all 3 phases down every street just in case one person wants it as it adds to the cabling required. No point in the OP going frantic. You want an industrial power supply? move to an industrial location.
That is not unfortunately the full truth.
Calculate how much power you can transfer with a single phase using amount X of copper. Then calculate same, using the same amount X of copper split for three phases.
As what you said, is a mathematically proven nonsense. Also, having separate loads on each phase create load imbalances and a lot more issues and stupid inconveniences.
I don't understand what you're getting at there.... Could you elaborate a little, please?
Three phase distribution can move 2-times more power per same amount of copper in the lines.
With that american split-phase thing, it is even more times.
That's why it's more then enough for a EUropean houshold to have just a 3x20 or 3x25A breaker panel. Even that is hell of a lot. (17 kW).
But we have 3 phase distribution here too, it's just not used for the last hundred feet or so, or the last couple miles in some cases where a more rural area is fed by only one of the phases. 17kVA would be considered grossly inadequate for typical US homes, the minimum standard is 200A 240V which is 48kVA. Looking at just the major loads in a typical home, 5.5kW clothes dryer, 2-3kW A/C, oven and cooktop 4-10kW, then if the house doesn't have gas, a hot water heater will be typically 4.4kW, electric heat pump 3-5kW, if they have electric resistance heat which was once widespread that can be 15-20kW just for the heating. I have natural gas for my heating, hot water and cooking but my hot tub is electric and pulls over 10kW when in use with both pumps and the heating on. Very little would change if I had 3 phase to my house, instead of 2x200A main it would be maybe 3x125A, and my house is not large or fancy by American standards.
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Yes it's kinda funny how a "typical" American house wiring is just single phase yet supply significantly more power than our typical European 3-phase house installation.
Yes, unsurprisingly, 1x200A is more than 3x25A or 3x35A.
Actually, we do have to think about balancing loads between phases which is an extra task and not always trivial, so 3x25A is actually somewhat less than 1x75A. Not much so, because largest loads are heaters connected in wye or delta with good balancing, but anyway.
The only thing our 3-phase house wiring really shines if you want to drive 3-phase motors directly off the mains. But that's quite a rarity anyway in households; small motors in household appliances are either brushed, or cap start / cap run.
We here seem to assume the USA is living in the stone age with their single-phase / split phase wiring, but that is obviously not true despite power systems being different. The cultural difference seems to be having higher power appliances available, yet here we concentrate on laughing at the 110V 15A plug and its incapability of delivering power, yet the real typical US cooktop is easily around some 10kW, something we won't see here at all.
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Yes it's kinda funny how a "typical" American house wiring is just single phase yet supply significantly more power than our typical European 3-phase house installation.
Yes, unsurprisingly, 1x200A is more than 3x25A or 3x35A.
Actually, we do have to think about balancing loads between phases which is an extra task and not always trivial, so 3x25A is actually somewhat less than 1x75A. Not much so, because largest loads are heaters connected in wye or delta with good balancing, but anyway.
The only thing our 3-phase house wiring really shines if you want to drive 3-phase motors directly off the mains. But that's quite a rarity anyway in households; small motors in household appliances are either brushed, or cap start / cap run.
We here seem to assume the USA is living in the stone age with their single-phase / split phase wiring, but that is obviously not true despite power systems being different. The cultural difference seems to be having higher power appliances available, yet here we concentrate on laughing at the 110V 15A plug and its incapability of delivering power, yet the real typical US cooktop is easily around some 10kW, something we won't see here at all.
looking at a few random stoves here and US they all seem to be around 10-11kW for four "burners" and an oven
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What about a stove clock then.
With 3-phases the clock can stay one no matter how lightning is flicking the lights.
All household ovens/stoves I've seen over here are built for Y/star wiring, i.e. phases to neutral. So the clock is powered only by one phase. The usual arrangement is one phase for the oven (including the clock) and two for the cooking plates. Breakers are 16A, so you can have 3 * 16A * 230V = 11kW at maximum.
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Yep here also all the ovens come with a 3 phase terminal block in the back to be able to spread the load over those phases. and 16A per phase is pretty typical of most large appliances. If you don't have 3 phase then you just wire all of them to the same phase. Induction cookers do a similar thing where they are built with 3 phase input, tho i have seen some weird 2 phase input on those too, it could get enough power from 2x16A so it just skips the third phase.
The supplemental electric heater used with our heatpump also is also 3 phase by simply having 3 separate heating elements to spread the load, much like the oven has multiple elements. But this is only a backup for cases where it might get really really cold and the heatpump might not keep up. Heating houses directly from electricity is never done here because its way too expensive. Maybe the US has so much cheaper power that it does not matter? Or is that only done in places where the winter never gets very cold? Power is about 6 euro cents per kW/h so heating a decent sized house would probably cost you like 1 grand per month.
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EUR 0.06 per kWh? Wow! We have to pay EUR 0.30 and more (average price might be around 0.33).
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In the state of California in the USA all the eco policies have progressively tiered pricing where many larger homes have a marginal rate at about $0.5 to more then $0.7 at KW/hr! Even the state of Hawaii has lower rates than CA.
The supply doesn't exist so they limit demand by having the highest prices most anywhere in the industrial world! People just suck it up and limit their use or pay the piper.
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Wow half a dollar for a kW/h? How much is the typical power bill per month then if houses are so power hungry to need a 200A service. Like a household spending >10 grand per year just on electricity?
Over here it costs up to 300€ in the cold winter months when a lot of power is used by the heatpump for heating, while a normal power bill tends to be under 100€.
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I believe the key is "progressively tiered", so the extreme rates are for people with BIG houses. Average rates paid rates are closer to $0.2/(kW*hr). Still expensive.
I don't live in California, but my employer is headquartered there and I visit fairly often (or used to). There are some really rich people in CA who would not even blink at a $10k annual electric bill.
Also, houses don't pull 200A all the time. The duty cycle is pretty low for the majority of people. Where I live, there is one transformer for each 3-5 people. They are not sized to handle all houses at full load for any length of time. I don't recall what the scaling factor is around where I live, though.
John
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On heating appliances like cooktops in the US, they are nominally rated for 240V operation, with three wires, L1, L2, and N (neutral). A higher-end one will pull a peak power of about 10 kW with all hobs on full and the oven going on full as well, i.e. 40A draw. If you look at the label, though, you will see that many have a reduced set of specs for 208V operation. This is because many newer apartments and condos in the US use 3 phase, and sqrt(3)*120v = 208.
On a tangential note, if you apply 120V from one of the lines to the neutral, you will activate "sales demo mode" where all the features and lights turn on, but the heating elements are not activated. It increases sales, or it did when people bought these in stores. Kind of like "store mode" for AV electronics.
John
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The supplemental electric heater used with our heatpump also is also 3 phase by simply having 3 separate heating elements to spread the load, much like the oven has multiple elements. But this is only a backup for cases where it might get really really cold and the heatpump might not keep up. Heating houses directly from electricity is never done here because its way too expensive. Maybe the US has so much cheaper power that it does not matter? Or is that only done in places where the winter never gets very cold? Power is about 6 euro cents per kW/h so heating a decent sized house would probably cost you like 1 grand per month.
I pay about 8 cents per kWh which is below the national average today. It used to be much cheaper when I was a kid, we lived in a 2500 sqft house that was all electric originally, heating was a central forced air electric furnace that was probably 20kW. In the mid 80s the subsidy on the hydro plants went away and electricity prices went up quite significantly, then not long after my area got natural gas service and my family upgraded to gas heating and hot water. Even today most apartments have electric resistance heat and hot water, I haven't seen resistance heat used in any newer houses though. This area has a mild climate but still gets cold in the winter, not like the Northern middle parts of the country though.
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Also, houses don't pull 200A all the time. The duty cycle is pretty low for the majority of people. Where I live, there is one transformer for each 3-5 people. They are not sized to handle all houses at full load for any length of time. I don't recall what the scaling factor is around where I live, though.
I don't know what is typical but I have one of those whole house energy monitors and my average consumption hovers around 270-300W when I'm home during the day and 400-600W when I'm awake in the evening. During the rare power outage that occurs I run my whole house pretty comfortably on a little 2kW inverter generator. I can't run the microwave, clothes dryer, air conditioner, the air compressor in my garage or other big loads but that big stuff is used only occasionally anyway. The peak I've seen in my own house was around 18kW which was a time when I was using the hot tub which I only keep filled part of the year, and had a load of clothes in the dryer and some other stuff going on. I have gas for heating, hot water and cooking, the latter was originally electric so my 200A service is probably larger than really needed today. For some reason most US home have electric stoves for cooking, even those that have gas to the house for heating and hot water. I prefer a gas stove and have never understood why they are not more popular here but I know some people fear the possibility of gas leaks, mostly older people who remember the days of standing pilots with no thermostatic control on the gas.