3phase to single phase current

[grumpydoc]

I'm rather confused by the topology here.

It sounds like the 10A or 16A "limiter" is actually a fuse or breaker feeding a set of sockets on one floor, this would be about the right value to feed something like 6-8 wall outlets.

In which case the supply coming into the house probably is rated at more than 10A per phase.

Benedict - perhaps a diagram showing the path from the supply coming into the building, through the meter and distribution boards and to each floor would be helpful. If you wish to use standard colours on the diagram for each phase then neutral is blue and the phases brown, grey and black. As it's an old installation in Croatia chances are the cables are different colours, maybe even non standard or inconsistent. In the UK at least the "old" phase colours are red, yellow and blue.

[langwadt]

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.

what a consumer can draw or what that section of wiring 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

you have wires for all three phase in every room?

if you only have 10A worth of wiring to room, you won't be able to get more than 10A no matter what you do

[IconicPCB]

Google Scott  transformer

Google Le Blanc transformer

[jlmoon]

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.

Wait now.. no way!!!  I have 100 Amps in my 14' x 14' lab.  4 separate quad outlet configurations protected with 20Amp breakers on one wall.  Your saying you only have 30 Amps at 240V to work with per floor?  How can you survive with that?

[grumpydoc]

Your saying you only have 30 Amps at 240V to work with per floor?  How can you survive with that?

It could be worse, in France the standing charge varies with the current limit, which goes up in stages from 3kW so you could find a property there is limited to 15A for the entire house 

A few weeks ago I stayed in a property which had a single phase supply limited at 30A/6kW**, it wasn't even anywhere remote but in the centre of a village.

**Handily if you push the button on the meter a few times it tells you what the agreed current limit is.

EDIT: Way back when I was involved in backstage work at Uni one of the stages had a 60A three phase supply (36kW) - the lighting guy for one of the bands turned up with a rig that needed about 3x the power, looked dismissively at the breakers and said "I've got a bigger power supply to me f***ing bathroom!!"

[jlmoon]

Your saying you only have 30 Amps at 240V to work with per floor?  How can you survive with that?

It could be worse, in France the standing charge varies with the current limit, which goes up in stages from 3kW so you could find a property there is limited to 15A for the entire house 

A few weeks ago I stayed in a property which had a single phase supply limited at 30A/6kW**, it wasn't even anywhere remote but in the centre of a village.

**Handily if you push the button on the meter a few times it tells you what the agreed current limit is.

So, that explains why I can't see all the country side lighting at night with GoogleEarth.  All the bulbs are around 10 - 15 watts max.  <Grins> 

[Benedict]

I didn't wire anything, have an idea about how thick the wires are but no real number (was 7 when the place was built). I can tell you they have done a baaad job, but it seems that at least the wires are ok.
They are single strand, but about 3-4mm in diameter.

I've done some research, and it seems the transformers are out of question. Too big, too expensive, too much hassle, for nothing.
I checked with the company's website, and it's infact six times 16 amps per branch, as you said. Which is perfectly fine for everything...

Unless you account that I have no three-phase outlets anywhere, and only one strand goes to e.g. 2 rooms. That means, if I turn on the heater, or the oven, and my pc at the same time, the circuit will break. Not to mention the sewer pump being on the same strand as the kitchen. Which I found out and rewired.

I'd draw a diagram, but I think it's easy enough to explain: One fat main cable from the company to me, branches into 4, one is neutral, other three have circuit breakers (fuses) limited to 16 amps (per floor). Then goes the big box which tells which rooms, lights, etc. are connected to which phase. The problem lies in the fact that whoever did the wiring did a horrendeous job of not getting all strands to some crucial locations, like the kitchen, or at least making some outlest in the room on one phase, and others on the other. Instead, I have a situation in which 2 rooms are wired together, and can't be rewired without breaking the walls (brilliant). The whole kitchen, and the living room, and the bedroom is wired together on one single phase. Insane.

So I've found a chart online: http://www.elteh.net/el-instalacije/tablice-limitatora.html

Mine is the lowest in the biggest chart, I have the 16/16/16 times 2, that'd be 11,04 kW x2. on 6 strands. Which means that while most of the power is useless, when you have to use for example 20 amps in 2 rooms which are wired together, boom nope. Terrible. And the kitchen too. Considering that my old place, a 100 year old building now, has the better wiring and, I think doesn't even have a company limit... sigh

And to upgrade, I'd have to cash out around 250/300 euros per 1kW, and it's only available from these options. The first table is the single phase. It might be possible to switch to that, seeing that due to the horrendous wiring, it's that or the rewireing the whole place. Which is .. you know.. really bad.
As i said, even if the wires were only 2mm, it's still enough for 20 amps or so, and they are deff. around 3 or 4 mm. Only prob is that they are really really badly connected, just in twists and insulating wire. That needs to change fast, I think.


So everyone, thank you very very much for helping me sort this out. I think I can do it from here on. Really, thank you all.

[langwadt]

I didn't wire anything, have an idea about how thick the wires are but no real number (was 7 when the place was built). I can tell you they have done a baaad job, but it seems that at least the wires are ok.
They are single strand, but about 3-4mm in diameter.

I've done some research, and it seems the transformers are out of question. Too big, too expensive, too much hassle, for nothing.
I checked with the company's website, and it's infact six times 16 amps per branch, as you said. Which is perfectly fine for everything...

Unless you account that I have no three-phase outlets anywhere, and only one strand goes to e.g. 2 rooms. That means, if I turn on the heater, or the oven, and my pc at the same time, the circuit will break. Not to mention the sewer pump being on the same strand as the kitchen. Which I found out and rewired.

I'd draw a diagram, but I think it's easy enough to explain: One fat main cable from the company to me, branches into 4, one is neutral, other three have circuit breakers (fuses) limited to 16 amps (per floor). Then goes the big box which tells which rooms, lights, etc. are connected to which phase. The problem lies in the fact that whoever did the wiring did a horrendeous job of not getting all strands to some crucial locations, like the kitchen, or at least making some outlest in the room on one phase, and others on the other. Instead, I have a situation in which 2 rooms are wired together, and can't be rewired without breaking the walls (brilliant). The whole kitchen, and the living room, and the bedroom is wired together on one single phase. Insane.

So I've found a chart online: http://www.elteh.net/el-instalacije/tablice-limitatora.html

Mine is the lowest in the biggest chart, I have the 16/16/16 times 2, that'd be 11,04 kW x2. on 6 strands. Which means that while most of the power is useless, when you have to use for example 20 amps in 2 rooms which are wired together, boom nope. Terrible. And the kitchen too. Considering that my old place, a 100 year old building now, has the better wiring and, I think doesn't even have a company limit... sigh

And to upgrade, I'd have to cash out around 250/300 euros per 1kW, and it's only available from these options. The first table is the single phase. It might be possible to switch to that, seeing that due to the horrendous wiring, it's that or the rewireing the whole place. Which is .. you know.. really bad.


So everyone, thank you very very much for helping me sort this out. I think I can do it from here on. Really, thank you all.

Just to sum up so you don't burn down the house.
 
If the wiring from the fusebox to the outlets in several rooms can only 10A it doesn't matter if you have
3x10A or 1x30A, those rooms can still only use 10A

[Benedict]

Hehe, thx for the warning. True, true. I think they are good for 50-60 amps or so, so no worries. I'll be certain to tripple check.

[Benedict]

Just to sum up so you don't burn down with* the house.
 

 

[Jeroen3]

Everything here is solid 2.5mm2. Thermally protected to 16 A type B per branch.
Tables say 22A, but in a wall next to other cables you must derate. I shall look this up in the reference guide tomorrow.

[max666]

Reading through this thread is bizarre!

I too just want to say, that there is nothing wrong with three phase installations in general, here in Austria every household gets three phases only (as far as I'm aware).

You say you now have the three phase plan 3 x 16 A / 11,4 kW (Tropolni limitatori za trofazni simetri?ni priklju?ak). But if you want to switch to one phase (Limitatori za jednofazni priklju?ak), you would have to get the 50 A plan to have the same 11,4 kW power rating. How much would that cost? Is the 1P 50 A / 11,4 kW option cheaper than the 3P 16 A / 11,4 kW option? I wouldn't think so.

Check your stove/baking oven, get the manual, or pull it out and look on the backside, if it can be connected with three phases. Most stove/baking ovens can be wired in various ways, like SeanB already explained nicely:

And if you have three phases coming in the door, then you should wire three phases to the stove/baking oven. Even if you switch to on phase, the oven should still be wired separately, with a separate circuit breaker, and should not just hang on the whole kitchen circuit as well. So if you don't have the wiring to the stove, you would need to pull separate wires anyway, regardless of how many phases you have.

All the other rooms and devices get as evenly as possible distributed over the three phases as well. Since I'm at it, a dishwasher, a washing machine or a dryer, each should have a separate wiring of 2.5 mm² cross-sectional area to a separate 16 A breaker. And all the separate 16 A / 13 A / 10 A breakers are connected to the main circuit breaker (which could be 3 x 16 A, although for a house that is pretty weak). Make yourself familiar with wire gauge http://en.wikipedia.org/wiki/IEC_60228 (not the best link, sorry), saying the wire is 3 mm thick doesn't mean anything. For example my oven has the following options and depending on that can have different wiring:


Now what is up with that heating? You aren't heating the house electrically, from the three phases, are you? That would be ridiculous, heating a house from 3 x 16 A, which by the way would make no difference if you had 1 x 50 A. Heating a house from 1 x 50 A is equally ridiculous. And heating electrically is the worst thing you can do, electricity is the most expensive energy carrier in terms of kW/€. But there is a big difference between heating your home electrically and cooking your food electrically, so just to clear that up what you actually do.
Also a picture of your main circuit breaker / fuse box might give us a better understanding too.

[Benedict]

Oh. Let me try to explain. What you speak are some valid points. Mostly not in my situation.

 

Is the 1P 50 A / 11,4 kW option cheaper than the 3P 16 A / 11,4 kW option? I wouldn't think so.

Should be exactly the same in price. I hope.

And heating electrically is the worst thing you can do, electricity is the most expensive energy carrier in terms of kW/€.
 

When you have the central heating of an object that is 350 meters squared of space, heating a living room and bedroom on one floor only, is much much better than heating the whole place with gas, when the rest of that space is "useless",don't you think? Closing the valves on all the other water radiators won't work, the thermostat is in different rooms/floors even. The house is broken. I'm trying to fix it/ make it usable at least for the time being. Why is the house so uselessly huge? I WAS 7 WHEN IT WAS BUILT not my fault

Check your stove/baking oven, get the manual, or pull it out and look on the backside, if it can be connected with three phases
 

Thx for the idea! It was mentioned already, will try it. HOWEVER, the whole kitchen, and one living room with it are wired on the same phase. There simply are not enough wires! Each outlet is a single phase one. As I said I don't have a single three phase outlet. Even if I did, the wiring in the house forbids it! I'd have to break down walls to correct that, I just might even have to eventually! It's terrible! My only hope is that these three outlets in the kitchen are somehow not wired together, and that I can rewire them on different phases. Somehow I have hope, we'll see. (Doubt it)

[mzzj]

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.

Like there would be a choice in many(most?) european countries.
Here in Finland pretty much all the houses built in last 70 years are connected to 3-phase.  3x 25A or 35A main fuses are the norm.  And all the power-hungry equipment is 3-phase. 9kW sauna stove, 6kW kitchen stove, 12kW for central heating etc.

OP should redo the wiring, I guess you should be able to find more competent electricians nowadays.  Run a 3x16A cable for the stove and so on.

[max666]

Ok so to get this perfectly clear, you DO HEAT the house electric (at least part of it), and when you turn on the stove, the breaker trips?

While you may have to pay less for a partially heated house on electric, than on a fully heated house on gas, I give you that, it's still not an optimal solution. But hey, customer is king here at the EEVbog

You could give us a count on how many heaters you have and how much kW they have, but I stand by what I said, heating and all the rest on 11,4 kW regardless of 3 x 16 A or 1 x 50 A, is ridiculous.
But hey, since you like tightrope walking, one thing you could do is get a clamp-meter http://www.batronix.com/shop/multimeter/clamp-multimeter.html and measure the currents on your 3 phases and then start juggling (the clamp-meter has the advantage that you don't have to disconnect phases for measuring the current)
Perhaps you can balance them out.

Since getting more than 11,4 kW connection is out of question, another thing you could do is wire the heaters on a contactor or individually on relays and have the heaters turn off when you turn on the stove or automatically when current on a phase exceeds a limit. This would actually be a solution that I kinda like, because it would allow you to maximise degree of capacity utilisation (which is to say you get the most out of your measly 11,4 kW connection). And turning off the heaters for a few hours is no big deal, because the thermal mass of the walls can bridge that.

I still would like to see how the stove is connected, how much power the stove has, if it is on the same circuit as the kitchen and what gauge of wire is used ... you know, burning down the house and safety and shit.
I'm not an electrician, but if they've used a 2,5 mm² wire (which should be good for 16 A, I guess) for the stove, kitchen and another room, and you're going to switch to one phase and you're connecting that all up to a 50 A breaker without checking the wiring, then you're on your own kid!!!

[M. András]

There should be plastic conduits in the wall where the wires are pulled in, remove 1 of the sockets carefully and check whats in there and if  the wires move at all, if it moves a bit you can pull in new ones and if the plastic pipes are big enough you can even pull in more or thicker wires, get a new distriution box and split the circuits so you can use multiple things at once.

The upgrade is sounds a bit costly on your end, it would cost me approx 310 euros to 3x25A infeed, apart from the rewiring of the whole building cos the 40 your aluminium wiring is now undersized and badly cooked joints slowly becoming a problem. that would be serious money which is split into 4 as its a 4 flat building, like 6-7 times what the upgrade would cost me after that

I have 3x16A 240v infeed which after the electricity meter is split into 20 circuits now eahc fused separately each phase goes trough 25A A-Si type schneider electric RCD-s then branched out to rooms, the only thing isnt protected by them is the stove as it runs off from 2x240v supply and i didnt brother to buy a 3 phase RCD for this, installed a 3ph+n surge arrestor too the catridge type as we had lots of damage last summer in a big storm all this is put into a 2x24 module schneider pragma enclosure, expensive and big but you cant beat the servicability of that breaker box,

[IanB]

There should be plastic conduits in the wall

This is not always the case. Sometimes the wires are just buried in the mortar.

[KJDS]

There should be plastic conduits in the wall

This is not always the case. Sometimes the wires are just buried in the mortar.

I've seen many  configurations, including clipped to the wall, then covered with a plastic trunk then plastered over, to left dangling free behind dot and dabbed plasterboard to straight plastered over.

Everything added to the last house I was in was put in the easiest way possible, so some sockets were mounted on the wall with a feed coming in from a socket on the other side of the wall. Others were mounted very close to the floor and the wiring channeled into the wall and then plastered over.

[M. András]

There should be plastic conduits in the wall

This is not always the case. Sometimes the wires are just buried in the mortar.

yeah but there should be, in my case we have nice little 16mm od plastic pipes in the walls, at every corner and joints it was broken into the wall then fixed with gypsum had to hammer out every corner when i redid the wiring, in the kitchen it had a 3cm long open section in the pipe which was full of gypsum so no way to pull out even the original wires, hope the drunk dude who did the originals installations is below the ground now by electrocution

[G7PSK]

Maybe you can buy a rectifier, and an inverter. This is probably the only way to convert 3p to 1p.

Scott transformer is what is normally used to convert 3 phase to single phase.

[IconicPCB]

Blueskull,

Earlier in the post I pointed to Scott transformer as well as to LeBlanc transformer.

Google is Your friend.

[Benedict]

Well, mum said she bought the plastic conduits, and found them throwing those away and just diping the wires into mortar. So, good job there. Though, that was for the coax ones.. Perhaps, and I do hope so.. the electric wires aren't. Will have to check it, it just might be possible to do the wires again, in which case I'm gonna install tanks in the walls. That house is just a nasty nest of problems

[Zero999]

It's not possible to use a transformer alone to draw power equally from all three phases and transmit it to a single phase.

A rotary converter (very bulky, mechanical so unreliable and inefficient) or rectifier plus inverter (better than a rotary converter but less efficient and not as tolerant of overloads as a transformer) are the only ways to do this.

[Jeroen3]

Here you go.
http://www.schaeferpower.com/content/content/acac-frequency-inverters
You have to ask the price. Which means its very expensive.