3 phase supply to domestic property!

[D4dog]

I have just moved into a new property, which is supplied with all three phases, to what looks like a distinctly industrial board - no RCD, just breakers. I think it was rewired by a DIY sparks about 26 years ago!

The incomiong supply is PME, but no attempt has been made to do any form of load balancing, and a common neutral is used.

It seems that the phases have been used at random to supply different parts of the house. In one case, the downstairs lights are on the same phase as a pump providing for the water supply. It is a heavy load, and when the pump is running, the lights pulse.

The question is, if a heavy inductive load is causing voltage fluctuations on one phase, will the problem be resolved by connecting eg lights to a different phase?

Second question - can I replace the old three phase disribution board with individual distribution boards with RCDs to each phase? It will just make my wiring easier !

Any thoughts?

Ta

 

[electronicsuk]

The incomiong supply is PME, but no attempt has been made to do any form of load balancing, and a common neutral is used.

Why would you expect anything other than a common neutral?

 

[mfarrow]

will the problem be resolved by connecting eg lights to a different phase?

Yes it will. Try to keep the phases balanced though in terms of loading. Have you got access to anything you can use to do some load monitoring?

can I replace the old three phase disribution board with individual distribution boards with RCDs to each phase?

I don't see why not - it's expensive otherwise.

 

[mikhailfaradayski]

might be a silly question, but is it a 1ph or 3ph motoor?

 

[RF Lighting]

Will the existing TP board not upgrade to RCBOs?

Do you know why you have a TP supply? Is it a huge house, or is there a large amount of electric heating?

Are you sure the installation is not balanced something like?

I'd be amazed if the pump really is a large load.

Any chance of a couple of photos?

 

[kai]

Correct me if I am wrong - many old pre-1960's houses had a three phase supply as standard, do not know why, as back then we had far less electrical appliances then we do now!

 

[FourFootMedia]

Correct me if I am wrong - many old pre-1960's houses had a three phase supply as standard

Usually just older town houses (comes in handy when converting them to flats as you just stick one flat on each phase).
Our house (1865) used to have a three phase supply, but we had 2 of them capped off and only use one now as paying for the three was pointless for our usage.

 

[D4dog]

To answer the first question - I point out that there is a neutral to assist in identifying that it is not a balanced industrial supply - which may or may not have a neutral, depending on how balanced it actually is.

I am not sure why the property has three phase. However, we are at the top of the hill, and probalby the last house on the supply line - it may simply have been convenient to provide a termination point for the supplier.

I am intrgued that me might have to pay more for having three phase - the meter is fed by all three phases (not sure how that is done, incidentally) - ie all three go in, and all three come out! But it is a common total readout.

The motor is only fed from one of the phases, so I assume it is single phase! - but as I said, they have been used at random. There is also a completely seperate distribution board, which isnt used at all. I think the house DID once rely soley on electric heating, which might explain the need.

i will try an provide photos later today!

cheers

 

[D4dog]

the electrics are stareting to become clearer! THe board that wasnt in use is for the original storage heaters - each one connected directly to its own breaker in the board! THis is controlled by a MEM Autoline connector controller (42ALCFP) , which is, I think, controlled from the time switch on the meter so it is only on during economy seven hours.

Given that the storage heaters are no longer used, does anyone know how I remove the timeswitch connection from the autoline unit, so that the unit is always connected, without upsetting the electric supplier, since I shouldnt be messing with the meter?

Any help appreciated?

 

[ericmark]

these boards by telemecanique have a neutral bar up the centre and are ideal for distributing single phase from a three phase supply but any RCD protection would be with RCBO's so it can get expensive the other way is to use a three phase isolator feeding three standard consumer units. The latter means changing phases becomes harder but not really a DIY job.

 

[Lectrician]

Why does having the neutral busbar included help with distributing single phase?

You do not need to use DP MCB's or MCCB's on single phase circuits. Nice too, but hardly ever done.

 

[D4dog]

I beleive I already have three seperate phases available. Whilst all three go to the meter, they then go to seperate distribtuion points, before being fed to the board. Can I simply unpick the boards, and connect three sepearate distribution units, one on each phase?