What is the different between American and European electric supply?

[Merlysys]

In North America we have both 110 and 220, the latter being for larger appliances. So is the American 220 identical to European 220?
This site says no...

Americans who have European equipment should not connect it to these outlets, since the phasing is wrong.
https://www.worldstandards.eu/electricity/why-no-standard-voltage/

By phasing do they mean frequency? (50 and 60 Hz)

Pictured is a NA panel. If scope probes are connected to L1 and L2 will the waveform shape be identical to if probes are instead connected to N and L1?

[richard.cs]

They probably mean the frequency is wrong, or just don't know what they're talking about. Some but not all appliances are frequency sensitive. Actually increasing the frequency is generally less harmful than decreasing it so most stuff would just work.

The appliance will see a different voltage relative to ground, but that's fine, all European appliances are designed to be safe and functional with any supply that puts 230V +/-10% 50 Hz across the N and L1 wires, irrespective of which side is grounded (some of Europe uses non-polarised plugs) or if it's a centre-tapped supply or connected between two phases of a (legacy) 230 V phase-phase supply.

[Brumby]

It's not a technical article - it's more an historical one.

The use of the phrase "phasing" by the author is unclear.  They may be referring to line frequency, but "phasing" is not the right word at all.  The phasing for 240V in the USA has to be right - or you wouldn't get 240V.

From my observation, there may be issues with a higher line frequency, but they are often overstated...

They probably mean the frequency is wrong, or just don't know what they're talking about. Some but not all appliances are frequency sensitive. Actually increasing the frequency is generally less harmful than decreasing it so most stuff would just work.

[Mjolinor]

That page has one or two facts and a whole pile of bolox.

Supply in the UK (and most of Europe) is either one phase AC 50Hz 230 volts WRT ground or three phase 230 volt WRT ground with the three phases being phased 120 degrees apart. That gives 400 volts phase to phase.

US supply is 110 WRT ground and in some installations it is biphase with two lives with 180 degree spacing giving a phase to phase of 220.

Japan has 100, 110, 120 and 240 single phase voltages depending on geographical location.

The reason for not connecting UK 230 volt stuff to two phases in the States is that you effectively make neutral 110 volts relative to ground and the appliances are designed to have neutral at ground potential or very close to it.

In the UK neutral is connected to the ground at the incoming cable termination for newer installations, there is usually the mother of all resistors at the MV / LV substation. This will be in the order of one ohm and will be the size of a typical garden shed connected between ground ( a nest of earth spikes) and the transformer output neutral.

The sum of any number of different phased, same frequency sine waves is always a sine wave.

[Zero999]

In the UK neutral is connected to the ground at the incoming cable termination for newer installations, there is usually the mother of all resistors at the MV / LV substation. This will be in the order of one ohm and will be the size of a typical garden shed connected between ground ( a nest of earth spikes) and the transformer output neutral.

What are you on about? There is no resistor. The neutral is bonded directly to the earth conductor, with as lowest resistance, as possible. Quite often the neutral and earth share a conductor, until the entrance to the premises.

[wraper]

The reason for not connecting UK 230 volt stuff to two phases in the States is that you effectively make neutral 110 volts relative to ground and the appliances are designed to have neutral at ground potential or very close to it.

This is not true at all. Only UK (type G), France (type F) and few others have polarized sockets. But I wouldn't count that live and neutral are wired properly. The rest of Europe (Type E) don't even have polarized sockets, and plugs are generally compatible with both type E and F, so there is not even much worth in polarization of French sockets. Polarization in UK sockets does not mean much as well, because most of appliances use removable power cable and can be used elsewhere with different cable. Also appliances which don't accept L an N wired both ways would be inherently unsafe and won't comply to safety standarts.

In the UK neutral is connected to the ground at the incoming cable termination for newer installations, there is usually the mother of all resistors at the MV / LV substation. This will be in the order of one ohm and will be the size of a typical garden shed connected between ground ( a nest of earth spikes) and the transformer output neutral.

Spreading even more blatant disinformation.

[iainwhite]

One observation:
The website "worldstandards.eu"  sound like an official standardization body or some such, but actually is operated by a Mr Conrad H. McGregor who is a campaigner for world standards in general.    I say treat with healthy skepticism (scepticism in the UK...)

[coppice]

In the UK neutral is connected to the ground at the incoming cable termination for newer installations, there is usually the mother of all resistors at the MV / LV substation. This will be in the order of one ohm and will be the size of a typical garden shed connected between ground ( a nest of earth spikes) and the transformer output neutral.

What are you on about? There is no resistor. The neutral is bonded directly to the earth conductor, with as lowest resistance, as possible. Quite often the neutral and earth share a conductor, until the entrance to the premises.

There isn't a resistor between neutral and ground, but there is often significant resistance. In UK installations you frequently see a volt or two between neutral and ground when the wiring is under high load. Inadvertent shorts between ground and neutral have caused fires in installations where there is nothing to pick up such shorts (i.e. no RCB). There isn't even a circuit breaker to limit the current when such a fault occurs.

[poorchava]

Most of the mid- and eastern europe use mix of Type E and Type F sockets ("Schuko"). Most earthed plugs fit both standards (CEE 7/7). Obviously because of idiots doing the wiring counting on the live wire being on the left as it should according to standard is a really bad idea.

Personally I don't understand why countries use 110V. When compared to 240V system, using 110V doubles the current and quadruples power losses for the same conductor thereby increasing power losses in wiring and forcing people to use thicker wiring which are heavier and more expensive.

[Mjolinor]

They no longer install resistors at the sub but there are still a lot installed. They are left over from pre PME systems where earth and neutral were separate conductors all the way from the substation. The UK system has been changing to PME for 30 years and as each network is changed earth spikes are fitted at each joint and only neutral and live are fed from the sub. Prior to that neutral and earth were not guaranteed to be at the same potential. The big resistor was to help prevent the earth potential rise under fault conditions. Neutral is classed as a "phase" wire when working on UK distribution networks.

There is no misinformation in my post. You can probably Google and prove all that I have said but do please do that before you tell me I am talking crap.

[wraper]

In the UK neutral is connected to the ground at the incoming cable termination for newer installations, there is usually the mother of all resistors at the MV / LV substation. This will be in the order of one ohm and will be the size of a typical garden shed connected between ground ( a nest of earth spikes) and the transformer output neutral.

What are you on about? There is no resistor. The neutral is bonded directly to the earth conductor, with as lowest resistance, as possible. Quite often the neutral and earth share a conductor, until the entrance to the premises.

There isn't a resistor between neutral and ground, but there is often significant resistance. In UK installations you frequently see a volt or two between neutral and ground when the wiring is under high load.

Voltage difference you see under load is nothing other than voltage drop on Neutral wire. Of course you won't see such voltage drop on Earth wire because there is basically no current flowing through it normally.

Inadvertent shorts between ground and neutral have caused fires in installations where there is nothing to pick up such shorts (i.e. no RCB). There isn't even a circuit breaker to limit the current when such a fault occurs.

I doubt this very much. All this would do is taking part of the load from Neurtal wire. And ground wire should be at least as beefy as live and neutral.

[wraper]

There is no misinformation in my post. You can probably Google and prove all that I have said but do please do that before you tell me I am talking crap.

Please google it yourself and provide the link. Because my google-fu is not good enough to find it.

[coppice]

A good reference for this issue might be the Philipinnes, as for historical reasons they use 220V 60Hz power, but neither wire is close to ground. The power is actually +-110V, so its like the US 220V arrangement, but every appliance in the house runs on that phase split 220V 60Hz power. So, you see a far broader range of appliances being run from split phase power than you do in the US.

Most plug in appliances sold in the Philipinnes are the same as the appliance sold in other 220V markets, with just the mains plug selected for local use. A few 220V 50Hz appliances don't like the 60Hz power, so a special version might be need. Typically, the Korean (also 220V 60Hz, but with the two wires being live and neutral) version of the appliance is OK for the Philipinnes. In some cases where the appliance is designed to be wired in it will have been designed with an assumption about the live and neutral inlets always being the right way around. There might then be issues with the assumptions made in the appliance's design. I have experienced this with a large UPS and some large computer and telecoms equipment. Either a specially adapted version was supplied, or an isolation transformer was supplied by the vendor.

So, the bottom line is a few appliances need to specially allow for split phase 220V 60Hz power, but mostly a piece of European 220V 50Hz equipment works just fine.

[Mjolinor]

There is no misinformation in my post. You can probably Google and prove all that I have said but do please do that before you tell me I am talking crap.

Please google it yourself and provide the link. Because my google-fu is not good enough to find it.

Well there's yer problem. It aint my job to educate you, sorry. Generally if I want to know something I go out and find about it rather than insulting people by telling them they are wrong because I don't know something.

[Mjolinor]

A good reference for this issue might be the Philipinnes, as for historical reasons they use 220V 60Hz power, but neither wire is close to ground. The power is actually +-110V, so its like the US 220V arrangement, but every appliance in the house runs on that phase split 220V 60Hz power. So, you see a far broader range of appliances being run from split phase power than you do in the US.

Most plug in appliances sold in the Philipinnes are the same as the appliance sold in other 220V markets, with just the mains plug selected for local use. A few 220V 50Hz appliances don't like the 60Hz power, so a special version might be need. Typically, the Korean (also 220V 60Hz, but with the two wires being live and neutral) version of the appliance is OK for the Philipinnes. In some cases where the appliance is designed to be wired in it will have been designed with an assumption about the live and neutral inlets always being the right way around. There might then be issues with the assumptions made in the appliance's design. I have experienced with with a large UPS and some large computer and telecoms equipment. Either a specially adapted version was supplied, or an isolation transformer was supplied by the vendor.

So, the bottom line is a few appliances need to specially allow for split phase 220V 60Hz power, but mostly a piece of European 220V 50Hz equipment works just fine.

I have designed things for use on the Philippine networks and can honestly say it is the strangest thing ever. I have never seen an HV/LV transformer that is fed only one phase wire, relying on the ground to provide the return other than there. Mind you twice a day the poles were underwater so a good ground was never a problem.

I have also never seen,other than the Philippines, any utility take an un-insulated HV (11kv) wire and make a horizontal loop on top of the poles within which are the LV meters in order to stop theft.

[richard.cs]

They no longer install resistors at the sub but there are still a lot installed. They are left over from pre PME systems where earth and neutral were separate conductors all the way from the substation. The UK system has been changing to PME for 30 years and as each network is changed earth spikes are fitted at each joint and only neutral and live are fed from the sub. Prior to that neutral and earth were not guaranteed to be at the same potential. The big resistor was to help prevent the earth potential rise under fault conditions. Neutral is classed as a "phase" wire when working on UK distribution networks.

There is no misinformation in my post. You can probably Google and prove all that I have said but do please do that before you tell me I am talking crap.

I've done a lot of work in LV distribution in the UK and I've never come across this. At MV (11 or 33 kV phase-phase) a resistor is normal between earth and the source transformer star point (which isn't distributed as all the transformers down to LV have delta primaries) to limit L-E fault currents on the MV network to a few thousand amps, but to my knowledge the same has never been common on LV in the UK. Historically pre-PME most supplies were either TT (earth rod) or TN-S, usually with copper conductors for L1, L2, L3 and N (sometimes an undersized N) and the lead sheath of the cable as E. The earth resistance might be a little higher than typical on PME but that's not due to an explicit resistor, it's simply that the lead sheath (or separate earth conductor in a few cases) had more resistance than the N in a modern system.

Voltage appearing between neutral and earth on a TT or TN-S relates to the voltage drop along the neutral, the earth resistance (maybe an ohm for TN-S, maybe a hundred for TT) doesn't come into it as that isn't where the current is flowing.

In PME/TNC-S where a single combined neutral-earth conductor runs from the substation to the customer intake where it then splits, the N-E voltage is usually much lower because there's less length where they are separate. It's normal for a few amps to flow in the customers earth conductor on these installations due to the N-E offset voltage under load but the earth conductors are sized for it. Very rarely a broken neutral-earth conductor in a PME system shunts enough load current into the customer earth terminal (and then into various earthed metalwork, especially metallic water mains which may be connected to someone else's PME earth terminal the other side of the break) to cause significant heating. I'm only aware of one fire caused by such but it's been a well-understood and much debated risk since the introduction of PME.

[wraper]

There is no misinformation in my post. You can probably Google and prove all that I have said but do please do that before you tell me I am talking crap.

Please google it yourself and provide the link. Because my google-fu is not good enough to find it.

Well there's yer problem. It aint my job to educate you, sorry. Generally if I want to know something I go out and find about it rather than insulting people by telling them they are wrong because I don't know something.

Nice. I tell you something dubious and you must believe it. If you cannot prove that I'm right, it's your problem  .

[Mjolinor]

There is no misinformation in my post. You can probably Google and prove all that I have said but do please do that before you tell me I am talking crap.

Please google it yourself and provide the link. Because my google-fu is not good enough to find it.

Well there's yer problem. It aint my job to educate you, sorry. Generally if I want to know something I go out and find about it rather than insulting people by telling them they are wrong because I don't know something.

Nice. I tell you something dubious and you must believe it. If you cannot prove that I'm right, it's your problem  .

Sorry, I don't see that. I don't have a problem with you not believing me, I do find it a bit sad that you find it necessary to berate me for it but I am man enough to allow you that luxury if you deem it necessary.

The reason that I found this out was that I was researching power line communications back in the early 90s on a specific network in Kendal. The results were not as expected because of this resistor. We were getting signals where we should not have because I assumed that where we put the signal in was ground and it wasn't anywhere near whereas the receiving end some 500 metres away had ground and neutral bonded. I was taken into the sub and shown the wiring including this massive resistor that gave us so many problems.

[coppice]

There isn't a resistor between neutral and ground, but there is often significant resistance. In UK installations you frequently see a volt or two between neutral and ground when the wiring is under high load.

Voltage difference you see under load is nothing other than voltage drop on Neutral wire. Of course you won't see such voltage drop on Earth wire because there is basically no current flowing through it normally.

Obviously.

Voltage difference you see under load is nothing other than voltage drop on Neutral wire. Of course you won't see such voltage drop on Earth wire because there is basically no current flowing through it normally.

Inadvertent shorts between ground and neutral have caused fires in installations where there is nothing to pick up such shorts (i.e. no RCB). There isn't even a circuit breaker to limit the current when such a fault occurs.

I doubt this very much. All this would do is taking part of the load from Neurtal wire. And ground wire should be at least as beefy as live and neutral.

I don't know the regulations where you are, but globally earth leads are typically thinner than the live and neutral. For example, in the UK houses are generally wired with what's called twin and earth cable. The type for a sockets circuit is 2.5mm^2 for the live and neutral, but only 1.5mm^2 for the earth wire. This sort difference in conductor size happens through the cabling heirarchy.

The fire hazard issue from massive unexpected earth currents is taken very seriously by people involved in fire safety. For example, the design of the original ethernet clamp on terminations for thick 10Mbps ethernet was extensively discussed, to ensure the design minimised any possibility of the barrier being breached by sloppy installation. Its not usually the heating effect in the cable itself that worries them. Its slightly resistive shorts, which can lead to a significant voltage drop + fairly high current in one tiny spot. If there are adjacent combustible materials you have a recipe for fire. Intermittent connections also have the potential for sparks to cause fires, even when the voltage difference is low.

[richard.cs]

The reason that I found this out was that I was researching power line communications back in the early 90s on a specific network in Kendal. The results were not as expected because of this resistor. We were getting signals where we should not have because I assumed that where we put the signal in was ground and it wasn't anywhere near whereas the receiving end some 500 metres away had ground and neutral bonded. I was taken into the sub and shown the wiring including this massive resistor that gave us so many problems.

That's interesting, was this definitely at LV? i.e. between the LV neutral (= star point of the 11kV/415V transformer) and earth?  Must be some odd legacy setup if that was in the public distribution network, but I am not sure why they'd do it unless this supply fed some specified piece of equipment or location that required limited fault currents. As I said it's normal to do this on MV and HV.

[Mjolinor]

The reason that I found this out was that I was researching power line communications back in the early 90s on a specific network in Kendal. The results were not as expected because of this resistor. We were getting signals where we should not have because I assumed that where we put the signal in was ground and it wasn't anywhere near whereas the receiving end some 500 metres away had ground and neutral bonded. I was taken into the sub and shown the wiring including this massive resistor that gave us so many problems.

That's interesting, was this definitely at LV? i.e. between the LV neutral (= star point of the 11kV/415V transformer) and earth?  Must be some odd legacy setup if that was in the public distribution network, but I am not sure why they'd do it unless this supply fed some specified piece of equipment or location that required limited fault currents. As I said it's normal to do this on MV and HV.

Absolutely sure it was LV. It may have been a specific modification for unknown reasons. The LV network went from MV/LV sub (11kv) to normal domestic / industrial supply but also to another NORWEB communication facility. I can see no reason for it being that way, it was a very old pre PME network but no other type of communications were ever used on it other than the stuff I was researching in the HF band. It had never had any of the earlier power line communication networks for SCADA using zero notch etc. I have never seen another on LV though was not told it was out of the ordinary at the time.

[Zero999]

The reason that I found this out was that I was researching power line communications back in the early 90s on a specific network in Kendal. The results were not as expected because of this resistor. We were getting signals where we should not have because I assumed that where we put the signal in was ground and it wasn't anywhere near whereas the receiving end some 500 metres away had ground and neutral bonded. I was taken into the sub and shown the wiring including this massive resistor that gave us so many problems.

That's interesting, was this definitely at LV? i.e. between the LV neutral (= star point of the 11kV/415V transformer) and earth?  Must be some odd legacy setup if that was in the public distribution network, but I am not sure why they'd do it unless this supply fed some specified piece of equipment or location that required limited fault currents. As I said it's normal to do this on MV and HV.

Absolutely sure it was LV. It may have been a specific modification for unknown reasons. The LV network went from MV/LV sub (11kv) to normal domestic / industrial supply but also to another NORWEB communication facility. I can see no reason for it being that way, it was a very old pre PME network but no other type of communications were ever used on it other than the stuff I was researching in the HF band. It had never had any of the earlier power line communication networks for SCADA using zero notch etc. I have never seen another on LV though was not told it was out of the ordinary at the time.

Now you seem to be saying it was one odd installation, rather than the norm. In your previous post, you implied this is very common.

I don't seem why you were offended. No one insulted you at all. If you say something unbelievable, don't be surprised if people tell you it's wrong.

[Mjolinor]

I am not offended by anyone telling me I am wrong. What offends me is that no one has proven it not to be the case and plenty of people were a bit more than pointing out a mistake in their attitude.

I was not led to believe it was anything out of the ordinary and have no reason to expect it to be so, I cannot see any reason why it should be. It is what it is and that is fact. If it was unique I do not know of a valid reason why and I have no idea why I was not told. To my mind if it had been a one off I would have been told and would have chosen a different network for the research.

I will not comment on this again and if someone would like the post deleting then ask and I will do so.

[newbrain]

And here I am, repeating myself once again.

Split phase 220V is the norm in most of Rome and close areas, coming from a 120V conversion (in the '70s, if I remember correctly).
And if one measure any phase to PE it's ~132V, not 110, as what was done was distributing a second phase from a triphase system, with a 10% overvoltage.

All appliances work of course correctly and no plug has ever been polarized (in my memory), "Shuko" (called "Siemens" in Italy), CEI 23-50 S17 (a larger Europlug, usually with PE) and Europlugs.

Nowadays PE and "differential breakers" (RCCBs) protect the users and the equipment, but never, ever, assume you have a neutral and a live wire.

[Zero999]

I am not offended by anyone telling me I am wrong. What offends me is that no one has proven it not to be the case and plenty of people were a bit more than pointing out a mistake in their attitude.

I was not led to believe it was anything out of the ordinary and have no reason to expect it to be so, I cannot see any reason why it should be. It is what it is and that is fact. If it was unique I do not know of a valid reason why and I have no idea why I was not told. To my mind if it had been a one off I would have been told and would have chosen a different network for the research.

I will not comment on this again and if someone would like the post deleting then ask and I will do so.

I don't see how deleting it would help anyone? Do you have any more information on the matter i.e. links?

[IanB]

In North America we have both 110 and 220, the latter being for larger appliances. So is the American 220 identical to European 220?
This site says no...

Americans who have European equipment should not connect it to these outlets, since the phasing is wrong.

To talk of "European" equipment here is not useful, since Europe has many different electrical standards, varying from country to country.

However, if the equipment concerned operates on a compatible voltage, and if the equipment concerned is not sensitive to the different AC frequency, then you could connect a European device to an American supply.

To take one example, the main difference between an American domestic 240 V supply and a UK 240 V domestic supply is the grounding/earthing arrangement. In the US outlet both legs of the 240 V supply are hot and are 120 V from ground. In the UK 240 V supply one leg is live and one leg is neutral (close to earth potential). In other European countries the supply voltage and grounding arrangements may be different.

As mentioned by other posters, European devices are designed to operate safely in a variety of different supply situations with both supply legs fully isolated and insulated from exposed parts. So a European nominal 230 V device can be plugged into a US 240 V socket without problems.

Personally I trust the design of European appliances more than US appliances. For instance, a stainless steel electric kettle in the UK will have a three pin plug and all exposed metal parts will be bonded to earth at the plug. A stainless steel kettle in the US (along with most other kitchen appliances) will have a two pin plug, a figure 8 zip cord and no grounding. Exposed metal parts are simply floating. I find this unnerving.

[jmelson]

In North America we have both 110 and 220, the latter being for larger appliances. So is the American 220 identical to European 220?
This site says no...

In the US, the typical residential supply is 120 -0-120, ie. a 240 V transformer secondary with a grounded center tap.  So, you will get a nominal 120 V from earth ground to either hot terminal.  Normal residential utility outlets deliver only one of these hot wires, so you get 120 V hot, and a grounded neutral.  This is single-phase power.  Rarely do single family residences have 3-phase power, but it is much more common in apartment buildings to have 3-phase available.  In those cases, you often have a 120-208 V (Wye) system, where any hot to hot wire measures 208 V, while any hot to neutral measures 120 V.

Much of Europe delivers 3-phase power to most residences, and is similar to the US Wye system, except the voltages are 230 V line to neutral, and 400 V line to line.
But, there's LOTS of variations in certain countries.

The US also has some odd systems in older industrial settings, often called open-delta.  One uses one center-tapped residential transformer to give both 230 V 3-phase power AND 120-0-120 single-phase supply for office loads from the same transformers and panel.  That is called center-grounded open-delta.  There is also a system called corner-grounded open-delta, that only gives 230 V 3-phase (or a choice of 230 V single phase loads).  These can be hooked up with 2-pole breaker panels, the same as used in residential service.

Jon

[coppice]

Much of Europe delivers 3-phase power to most residences, and is similar to the US Wye system, except the voltages are 230 V line to neutral, and 400 V line to line.

The only European country where 3 phase for domestic installations is the norm is Germany. Domestic 3 phase exists elsewhere in European, but its not the standard practice. Most streets have 3 phase power, and they spread the phases out across the houses.

[tooki]

In North America we have both 110 and 220, the latter being for larger appliances.

No, we don’t. (I’m American.) We have 120V/240V. It hasn’t been 110/220V for over 70 years.

[Brumby]

Personally I don't understand why countries use 110V. When compared to 240V system, using 110V doubles the current and quadruples power losses for the same conductor thereby increasing power losses in wiring and forcing people to use thicker wiring which are heavier and more expensive.

This is one question that the article cited by the OP actually addresses ... so I suggest you read it.

[Brumby]

In North America we have both 110 and 220, the latter being for larger appliances.

No, we don’t. (I’m American.) We have 120V/240V. It hasn’t been 110/220V for over 70 years.

Patience, my friend.

It took me more than a year of browsing through this forum for that information update to come to light.

[Nusa]

In North America we have both 110 and 220, the latter being for larger appliances.

No, we don’t. (I’m American.) We have 120V/240V. It hasn’t been 110/220V for over 70 years.

Half-right. The nominal STANDARD has been 120V/240V for over 70 years. However, that standard was for new infrastructure. It took many decades for existing infrastructure to make the switch, so what you grew up with depended on where you lived. So way less than 70 years in practice. It's even possible there are still a few pockets left today, although I'm not aware of them.

You also have to remember it's a nominal service voltage. An actual utilization voltage of 110V at the customer plug in a house is low, but still acceptable within the current standard.

[Brumby]

So way less than 70 years in practice. It's even possible there are still a few pockets left today...

I keep this in the back of my mind as well.

[IanB]

The supply voltage is absolutely 120/240 where I live. I have measured it multiple times and it is regulated to within a couple of volts all through the day.

[poorchava]

Much of Europe delivers 3-phase power to most residences, and is similar to the US Wye system, except the voltages are 230 V line to neutral, and 400 V line to line.

The only European country where 3 phase for domestic installations is the norm is Germany. Domestic 3 phase exists elsewhere in European, but its not the standard practice. Most streets have 3 phase power, and they spread the phases out across the houses.

Not the only one. It's the same at least in Poland and AFAIK Czech Republic and Slovakia too.
It is true that there is rarely a 3-phase socket in apartments. Most electric kitchen stoves require 3-phase supply but they are usually wired directly to a terminal block in the wall. This is standard, as gas most new apartment complexes don't have gas. Loads other than ovens are usually just connected to different phases to even out the load.

With houses it is different. Many will have a 3-phase outlet in basement or garage. If they don't, it's usually the case of the owner not needing more than anything else.

Some older buildings don't have a separate PE wire. Before nineties the standard way was to use a PEN wire which is protective Earth and neutral at the same time.

[Vtile]

Bollocks there is no PME/MEN only TN-C-S according the specified IEC standards. 

[Vtile]

Much of Europe delivers 3-phase power to most residences, and is similar to the US Wye system, except the voltages are 230 V line to neutral, and 400 V line to line.

The only European country where 3 phase for domestic installations is the norm is Germany. Domestic 3 phase exists elsewhere in European, but its not the standard practice. Most streets have 3 phase power, and they spread the phases out across the houses.

Nope, this is norm also in atleast Finland and I'm pretty confident it is also standard in Sweden from some non-directly related material I have seen. Every new household will have 3-phase as the standards promote to wire the electric stoves as 3-phase, also traditionally the Saunas and other elecrical heating have been a major power hogs, so the 3-phase installations have been natural to have. Norway on the other hand have a bit more quirks IIRC compared the current IEC specifications.

[poorchava]

Another thing that usualy requires 3-phase power: at least here in Poland electrical floor heating has become quite popular over last few years because it is easier and cheaper to install in comparison to water systems and can easily be retrofitted in existing flats/houses. My house is about 160 sq.m of floor area, which at roughly 100W per sq.m is ~16kW. Good luck drawing that from a single phase (that is - aside from the fact that I actually happen to have a transformer station a few meters from the border of my property and I could potenttially get about 40kW per phase if I had that kind of money and needed to). And this is not a particularily large house or an exceptionally high-powered heatin system.

[IanB]

My house is about 160 sq.m of floor area, which at roughly 100W per sq.m is ~16kW. Good luck drawing that from a single phase

At 240 V that would be 67 A. If the house had a 100 A supply that would be achievable, although it would need some very thick wires.

[sibeen]

I have designed things for use on the Philippine networks and can honestly say it is the strangest thing ever. I have never seen an HV/LV transformer that is fed only one phase wire, relying on the ground to provide the return other than there. Mind you twice a day the poles were underwater so a good ground was never a problem.

Very common in Australia and New Zealand. It's called a SWER (Single Wire Earth Return) system. When you're running power out 100s of kilometres to feed voltageer to three people and a million rabbits it's an economical solution.

[paulca]

In North America we have both 110 and 220, the latter being for larger appliances.

No, we don’t. (I’m American.) We have 120V/240V. It hasn’t been 110/220V for over 70 years.

Patience, my friend.

It took me more than a year of browsing through this forum for that information update to come to light.

Similarly the change to the UK voltage that happened decades ago and lots of people still refer to the mains as 240V when it hasn't been for decades to bring it more inline with the 220V european standard.  I believe it is now 230V +/- 10%.

Older devices, in the 1970s/1980s used to have manual switches on the power inlets for 220V / 240V supplies, but these days they are almost all auto switching (or designed not to care).

[sibeen]

Australia did what the UK did, just a few years later. Our 'standard' voltage changed from 240 to 230 volts. Out actual delivered voltage changed this much ---><-------.

[richard.cs]

The UK is currently 230 V +10%/-6%, note the asymmetric tolerance, giving a range of 216 to 253 V, having previously been 240 +/-6%, 226 to 254 V. Nothing has changed except the specification. It's still 240 V nominal even on new installs, and a lot of substations are on the 250 V (433 V phase-phase) tap anyway giving voltages in the mid 240's to many customers. I measured mine as 239.9 V last night but routinely see around 246 V.

[jonovid]

Australia did what the UK did, just a few years later. Our 'standard' voltage changed from 240 to 230 volts. Out actual delivered voltage changed this much ---><-------.

in South Australia its 250 volts at the outlet.

[VEGETA]

Here in Jordan we have 220v single phase  @ 50 Hz. That is why we get "European plug" option when we buy from Ebay.

[IanB]

Similarly the change to the UK voltage that happened decades ago and lots of people still refer to the mains as 240V when it hasn't been for decades to bring it more inline with the 220V european standard.  I believe it is now 230V +/- 10%.

That's why I started this other thread.

The UK mains is still regulated to a nominal 240 V, even though there is a wide allowable variation. You could join in the fun and measure your own voltage to find out how close yours is.

[Paul Moir]

My house is about 160 sq.m of floor area, which at roughly 100W per sq.m is ~16kW. Good luck drawing that from a single phase

At 240 V that would be 67 A. If the house had a 100 A supply that would be achievable, although it would need some very thick wires.

In North America, a 200A service is normal for a house with electric heat.   100A would be about the smallest you would ever install nowadays, especially since 125A doesn't add much cost:  just slightly larger wires on the service.  Back in the '50s and '60s 60A was common around here which was enough to run your fridge, furnace, electric water heater, stove, lighting etc.  Unfortunately these got pushed over the edge by the popularization of the electric clothes dryer.

[richard.cs]

In North America, a 200A service is normal for a house with electric heat.   100A would be about the smallest you would ever install nowadays, especially since 125A doesn't add much cost:  just slightly larger wires on the service.  Back in the '50s and '60s 60A was common around here which was enough to run your fridge, furnace, electric water heater, stove, lighting etc.  Unfortunately these got pushed over the edge by the popularization of the electric clothes dryer.

In the UK supplies of between 60 A and 100 A are normal for domestic. Very large houses that need more power would be more likely to have 3-phase than to go above 100 A single phase. Most houses use natural gas as the primary source of heating, and many electrically heated houses use storage heaters which are heated overnight on cheap-rate electricity (when there are few other loads). Domestic clothes driers tend to be 2.5-3 kW here so they aren't a major consideration for us.

[Paul Moir]

Owing to the higher voltage then, the laws of physics haven't changed.  The 3-4kW the dryer took a good chunk of the 14kW available from those old 60A 240V services.
In my location, the price of domestic electricity is regulated which has so far not allowed variable rates.  Businesses are typically charged based on consumption and peak demand.  This means that there is no cheap rate for domestic, but large businesses might schedule loads to reduce their peak. 
Heat by combustion is very popular here naturally.  Where I live is gas deprived so heating by "fuel oil" (diesel) was by far the most common method.  It seems to me the popularity of electric heat was tied to the price of oil which is of course not so regulated.  This peaked in the 80s with both the price of oil being very high and interest rates being very high.  The capital cost of cheap resistive heaters is much less than that of a furnace.
Three phase is unfortunately not available in most residential districts by the nature of the distribution network.  A single conductor at typically 12.5kV-25kV is transformed down and feeds a few houses.  Three phase would require three wires and three transformers.  Out in the country they use a single conductor and a small single transformer for each house.

[tooki]

In North America we have both 110 and 220, the latter being for larger appliances.

No, we don’t. (I’m American.) We have 120V/240V. It hasn’t been 110/220V for over 70 years.

Half-right. The nominal STANDARD has been 120V/240V for over 70 years. However, that standard was for new infrastructure. It took many decades for existing infrastructure to make the switch, so what you grew up with depended on where you lived. So way less than 70 years in practice. It's even possible there are still a few pockets left today, although I'm not aware of them.

You also have to remember it's a nominal service voltage. An actual utilization voltage of 110V at the customer plug in a house is low, but still acceptable within the current standard.

Well obviously we are talking about the nominal voltage, if not otherwise specified! And in USA, the nominal voltage has been 120V for the better part of a century. That’s what we should be stating and encouraging, not 110 just because it’s still within spec if that happens to be the actual voltage.