3phase to single phase current

[Benedict]

Hi all, I have a peculiar situation. At the time my family was building our house; as it's common in our country, we were deceived. I've already repaired an entire floor of electrical instalations (for example guys didn't connect the ground in our sockets (not in the sockets themselves, in the boxes in the walls infact), and then couldn't diagnose it, insisted there was no voltage there, and that my contactless detector was wrong - imagine that. LED lights were still functioning (no idea why, probably such a small current managed to ground itself somehow), and my tesla coil worked, I'm guessing cause it grounded itself wirelessly.) I have also repaired the phone/internet installations that they (I'm guessing on purpose) broke / left disconnected in the walls, most likely so we have to call them again, to charge us again. For their incompetence. We can't sue them, our justice system is broken. We built the house legally even, which is sortof a rarity in our country... so tl:dr : these same douchebags of electricians, told my mom (at the time i knew nothing about the subject) that it's better that we got triphase current. Some lies were told i reckon, why in the world would a family house profit from a triphase solution... Now we have limiters on each phase, such that we cant even cook normaly. Redoing the whole instalations seems out of question now. I guess if I decide to get an industry running in my house, I'm at advantage!

So, is there ANY normal way to convert the triphase into normal single one? I've done extensive googling, but any solutions have almost no exeptable efficiency, or those that do, are reeeeeally expensive. Thx for any info/ideas

[Simon]

If you take two of the three phase wires on a Delta system all the earth and one of the phases on a star system you can use those as a single phase. What normally happens is that the power is delivered in the form of three-phase and then one of each phase goes to a different street so every third street for example you could get the same phase. It is then hoped that the average consumption of all the houses or balance throughout the three phases. If you have a star system you could in fact put your lights on one phase, your sockets on another or maybe different floors on different phases. That way they would still share the same neutral. The problem you are having with the cooker sounds like a problem with the capacity of the wiring, the safety breaks, or the amount of power being delivered to the house in the first place.

[Benedict]

That's indeed the problem, yes. What you have described is what I did infact, I've tried to rationally distribute the phases around the house. It's how we have "single" phases, and why I can't use powerline ethernet adapters between the floors (different phases). Each phase can give around 10 amps of current or so. So basically, I can't use 12 amps when needed in one place shortly, even though the other 18 are left unused, cause the phase only allows 10, period. What I'm trying to do is infact convert these 10 amps per 3 phase limiters into one phase that could distribute the load between the 3 original phases. Thx for your response!

[Benedict]

The thing is, I have 4 wires. Three phases, and one neutral. So you're saying, I can just connect 2 of the "phase" wires and neutral together, and use that with the remaining phase as a "single phase" system? Not sure that'd work..

[Monkeh]

So you're saying, I can just connect 2 of the "phase" wires and neutral together

FUCK NO.

You have 3-phase. That's it, you're stuck with it. That should only be a limitation for ovens and the like, which are easily enough available with low current elements designed for multi-phase installations. That's your only sane option.

Sidenote: You had a house BUILT and now you're trying to use PLT? ........

[Benedict]

So you're saying, I can just connect 2 of the "phase" wires and neutral together

FUCK NO.

Thought so. Guess I misred the first reply.

When the house was built, I was 7 years old. Don't blame me for getting stuck with that system. It's not just the ovens. In winter, you can't have more than one heater in the entire phase, and that sucks big time. My mom actually bought the thermal insulation,  which the builders nicely threw away..
I need the stupid homeplugs cause the same guys made it impossible to get the wiring between the floors in some normal way. Ugh it's complicated

[Monkeh]

Electric heating.

With 7.2kVA at your disposal.

 

[SeanB]

I take it you are referring to use of an electric stove being the problem, with it tripping the mains if you try to use more than 2 plates together?

In that case you simply remove the power connection cover on the back, where you will see that the incoming single phase cable ( line, neutral and protective earth) goes to a 5 terminal block, which is labelled L!, L2, L3, N and then a bolt or another terminal for protective earth. Incoming cable will go to one of L1,L2 or L3 for the line wire ( either red or brown in the cable) and another will go to neutral ( either black or light blue) and the third will be a yellow/green to the protective earth.

There will be 2 bridge links ( either a set of jumpers or pressed metal links depending on how old the stove is and where it comes from) combining the L1, L2 and L3 terminals. Simply remove them and wire the stove to the 3 phase power that you have, using a 5 wire flexible cable. that will work to spread the load over the 3 phases when you have more than 1 plate on at a time. You might still have issues using the oven and grill in combination with some plates, but you can simply not use that combination and use another plate.

[Simon]

As suggested you may find that your cooker can use all three phases. Alternatively you could potentially rewire it to redistribute power to each element so that they take a phase each although you would need to know what you are doing here.

The other main problem is that you only have 30 A in total, I think in the UK any household has a single phase capable of more than 30 A more like 60 A so you are short on power in the first place.

As for heating surely a modern house has gas available? Electric heating is quite expensive.

[Benedict]

It's really quite simple. 30 amps + another 30 from the other floor would be more than sufficient to heat anything and have enough current to do whatever you need combined with the central heating we have (it has to be toned down as gas gets crazy expensive and, as i said, I'll have to redo the entire thermal insulation, not sure what to do). We don't live there, so it's not an issue now, still, I'd like to move there one day perhaps. Only nope, i got 10 amps limit on each phase. Not to mention all the other problems. Considering selling the place.

I take it you are referring to use of an electric stove being the problem, with it tripping the mains if you try to use more than 2 plates together?

In that case you simply remove the power connection cover on the back, where you will see that the incoming single phase cable ( line, neutral and protective earth) goes to a 5 terminal block, which is labelled L!, L2, L3, N and then a bolt or another terminal for protective earth. Incoming cable will go to one of L1,L2 or L3 for the line wire ( either red or brown in the cable) and another will go to neutral ( either black or light blue) and the third will be a yellow/green to the protective earth.

There will be 2 bridge links ( either a set of jumpers or pressed metal links depending on how old the stove is and where it comes from) combining the L1, L2 and L3 terminals. Simply remove them and wire the stove to the 3 phase power that you have, using a 5 wire flexible cable. that will work to spread the load over the 3 phases when you have more than 1 plate on at a time. You might still have issues using the oven and grill in combination with some plates, but you can simply not use that combination and use another plate.

This is great. Thx for that info, might save me a lot of trouble!

As suggested you may find that your cooker can use all three phases. Alternatively you could potentially rewire it to redistribute power to each element so that they take a phase each although you would need to know what you are doing here.

The other main problem is that you only have 30 A in total, I think in the UK any household has a single phase capable of more than 30 A more like 60 A so you are short on power in the first place.

As for heating surely a modern house has gas available? Electric heating is quite expensive.

Gas is even more expensive for some reason here. At least that's what bills say. I might be wrong, it might even be 16 amps per phase.. That just sucks cause where I live right now, we have basically unlimited single phase current :/
Some new law or something. You have to pay to get limits up, a new way to squeze money from people.

Thx for your info folks, will help a lot!

[Phaedrus]

I would just redo the entire electric system. Whoever hooked it up in the first place was an idiot, or a scammer. As for selling it, passing this mess off on some other poor Joe seems cruel.

[M. András]

well you can check that if its fused for 10 amps in the user side breaker panel per phase or its fused 10 at the electricity meter which in case i think you have to contact the utility company to upgrade

[Benedict]

I would just redo the entire electric system. Whoever hooked it up in the first place was an idiot, or a scammer. As for selling it, passing this mess off on some other poor Joe seems cruel.

Thought about that too, I have no idea how much it'd cost to redo everything :S
And yeh it'd be cruel yes

well you can check that if its fused for 10 amps in the user side breaker panel per phase or its fused 10 at the electricity meter which in case i think you have to contact the utility company to upgrade

And that upgrade is off the charts. It's just insane price, especially for three phases, I'd need to get every phase upgraded, and prices are just insane



I was considering something like this : http://carroll-meynell.com/technical-3phase

[Seekonk]

If you actually have three phase at each outlet, that could be workable.  Each outlet could expand to be three circuits.  If higher current is needed use a transformer between two phases. 

[SeanB]

Go back to single phase then, and simply get a new meter with a 60A connection. That way you only have to replace the cable from the meter to the distribution board if it is not 16mm cable, otherwise you just reuse it.

[Benedict]

If you actually have three phase at each outlet, that could be workable.  Each outlet could expand to be three circuits.

Each floor has 4 main wires, each phase wire limited to somewhere between 10-16 amps. I think one floor is limited to just 10.

If higher current is needed use a transformer between two phases.

THIS! How! This is what I was looking for!

Go back to single phase then, and simply get a new meter with a 60A connection. That way you only have to replace the cable from the meter to the distribution board if it is not 16mm cable, otherwise you just reuse it.

Never done something like that before, is it generally posible to just ask the provider nicely to give me single phase back?

[Cloud]

For how much are rated the main fuses? Do you have automatic fuses or the ones with the melting innercore (diazet). Because through diazet ones can current can be 1.8x higher and it wont brake it.

[Benedict]

All fuses and limiters are automatic. My fuses are not the problem, it's the distributers fuses (limiters) - really fast type ones too. They are, iirc, 10 amps per phase + one neural one (no limit) one floor, and 16 amps per phase + one neutral (no limit) on the other. Voltage is 220 volts.

[langwadt]

That's indeed the problem, yes. What you have described is what I did infact, I've tried to rationally distribute the phases around the house. It's how we have "single" phases, and why I can't use powerline ethernet adapters between the floors (different phases). Each phase can give around 10 amps of current or so. So basically, I can't use 12 amps when needed in one place shortly, even though the other 18 are left unused, cause the phase only allows 10, period. What I'm trying to do is infact convert these 10 amps per 3 phase limiters into one phase that could distribute the load between the 3 original phases. Thx for your response!

you are in over your head, your problem has nothing to do with single or three phase.

you can't use more than 10A from a single outlet because the wiring and the outlet isn't  rated for more and thus there is a fuse of 10A

you can easily use much more the 10A per phase, but it requires would require several outlets each with separate wiring to the distribution box and a 10A fuse

[Benedict]

That's indeed the problem, yes. What you have described is what I did infact, I've tried to rationally distribute the phases around the house. It's how we have "single" phases, and why I can't use powerline ethernet adapters between the floors (different phases). Each phase can give around 10 amps of current or so. So basically, I can't use 12 amps when needed in one place shortly, even though the other 18 are left unused, cause the phase only allows 10, period. What I'm trying to do is infact convert these 10 amps per 3 phase limiters into one phase that could distribute the load between the 3 original phases. Thx for your response!

you are in over your head, your problem has nothing to do with single or three phase.

you can't use more than 10A from a single outlet because the wiring and the outlet isn't  rated for more and thus there is a fuse of 10A

you can easily use much more the 10A per phase, but it requires would require several outlets each with separate wiring to the distribution box and a 10A fuse

No, you got me wrong. Not the single outlet, no. The problem is that entire rooms (more than 1) and some pumps and what not is on that one 10 amps limiter. I'm not trying to power up the millenium falcon from one of my outlets

[Zero999]

If higher current is needed use a transformer between two phases.

THIS! How! This is what I was looking for!

Yes, that will work.

Two 10A 230V phases would give 400V at 10A which is 4kVA which would give 17.4A at 230V on the secondary, assuming no losses but in reality it'll be under 17A. Unfortunately transformers are big, bulky and expensive.

[Benedict]

If higher current is needed use a transformer between two phases.

THIS! How! This is what I was looking for!

Yes, that will work.

Two 10A 230V phases would give 400V at 10A which is 4kVA which would give 17.4A at 230V on the secondary, assuming no losses but in reality it'll be under 17A. Unfortunately transformers are big, bulky and expensive.

So I'm guessing I'm better off forgeting about it?

[langwadt]

That's indeed the problem, yes. What you have described is what I did infact, I've tried to rationally distribute the phases around the house. It's how we have "single" phases, and why I can't use powerline ethernet adapters between the floors (different phases). Each phase can give around 10 amps of current or so. So basically, I can't use 12 amps when needed in one place shortly, even though the other 18 are left unused, cause the phase only allows 10, period. What I'm trying to do is infact convert these 10 amps per 3 phase limiters into one phase that could distribute the load between the 3 original phases. Thx for your response!

you are in over your head, your problem has nothing to do with single or three phase.

you can't use more than 10A from a single outlet because the wiring and the outlet isn't  rated for more and thus there is a fuse of 10A

you can easily use much more the 10A per phase, but it requires would require several outlets each with separate wiring to the distribution box and a 10A fuse

No, you got me wrong. Not the single outlet, no. The problem is that entire rooms (more than 1) and some pumps and what not is on that one 10 amps limiter. I'm not trying to power up the millenium falcon from one of my outlets

by limitir I assume you mean fuse?

if the wiring to that room is only good for 10A there is nothing you can do other than pull more wires each with a separate 10A fuse

[Benedict]

by limitir I assume you mean fuse?

Yeah. It is a fuse. But it's called a limiter here, just the technical term for that specific fuse, as it limits what a consumer can draw.

if the wiring to that room is only good for 10A there is nothing you can do other than pull more wires each with a separate 10A fuse

Aaaand that's what I want to avoid. I see no way of doing that withough drilling through the walls. I was wondering if something like open delta 3 to single exists, and within reason

[Jeroen3]

So I'm guessing I'm better off forgeting about it?

You should ask (and pay) an certified* electrician (and possibly grid company) if it's possible to install 25A rated 3 phase main fuse and 16A (3kW)(or less) per branch. Which is common around here, we have 6x16A branches in our house. Living room, first floor, attic, garage, central heating system and washing machine.

Assuming you didn't wire up the house with puppy hairs, this might be a realistic and affordable solution.
What mm2 and stranding did you use?

If the (above ground?) main grid in your street is not able to perform better than 10A per phase per building, you're probably out of luck.

*Insurance companies will not pay if he/she was not certified
edit:
We keep saying fuse. Isn't a MCB (miniature circuit breaker) better?