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Hi everyone i have recently had a 3 phase supply and board install in a domestic house, this will supply the house which has 12 circuits for light ring mains and ac units etc as well as in the future a 3 phase workshop, single phase workshop, 2 x 1 bed lodges, hot tub, solar panels and electric car point, do all the circuits in the house need to be on the same phase or can they be split across the 3 phases.
 
There used to be a regulation about 400v warning labels if any 2 phases were close to each other...(2m I think?) such as cooker supply on one phase, nearby socket on another.
Luckily that reg no longer exists.

best to balance the load.... but as other large single phase items are added, you may need to move things around to keep it balanced.
 
There is a regulation on labelling things when voltages above the typical 230V might be found, for example, grid switches fed from multiple phases where 400V between them exists.

It is unlikely that loads such as lighting or the sockets on a given floor would be a phase-balance issue, so might be an idea to try and keep them all on one phase where they may be close or share a switch/junction box and look to the big loads (shower(s), hot tub, EV charge, etc) for trying to maintain balance / total capacity.
 
Can you quote a regulation number for that?
514.10.1 was what I was thinking of.

Though it is seems to be talking only about 230V to earth, whereas I was remembering it has talking about voltages above 230V where not expected (e.g. DIY discovering 400V phase-phase on a domestic setup).
 
514.10.1 was what I was thinking of.

Though it is seems to be talking only about 230V to earth, whereas I was remembering it has talking about voltages above 230V where not expected (e.g. DIY discovering 400V phase-phase on a domestic setup).

Yes, labelling is only required when Uo exceeds 230V, so for for any normal LV supply in the UK that labelling is not required.
The regulation requiring labels for anything voltage above 240 was removed/changed a long time ago, I have a feeling it was last seen in the 14th edition.

This is a pet hate of mine, the theatre industry is slightly obsessed with this 'phase seperation' to the point that people will make an installation wildly out of balance just to be able to have >2m between points on different phases.

Plus I don't like seeing equipment covered in unnecessary stickers such as 400V warning splattered all over equipment that otherwise looks quite neat and tidy.
 
The Regulation changed in one of the amendments to the 17th Ed. This is the Regulation from the first Ed of the 17th Ed but was amended in later versions. 3 phase 20200710_090532 - EletriciansForums.net
 
Yes, labelling is only required when Uo exceeds 230V, so for for any normal LV supply in the UK that labelling is not required.
The regulation requiring labels for anything voltage above 240 was removed/changed a long time ago, I have a feeling it was last seen in the 14th edition.
OK, that explains it.

This is a pet hate of mine, the theatre industry is slightly obsessed with this 'phase separation' to the point that people will make an installation wildly out of balance just to be able to have >2m between points on different phases.

Plus I don't like seeing equipment covered in unnecessary stickers such as 400V warning splattered all over equipment that otherwise looks quite neat and tidy.
I also remember the old "2m rule" which, as you say, is very troublesome in many setups where you need 3-phase simply for total power but then it is hobbled by not being able to keep a sensible balance.

I had imagined the label rule still applied as the MK grid switch boxes I recently got came with 400V warning stickers. A lot of stuff seems more sticker than equipment these days :(
 
Must be a first that voltage warning labels have been made all but redundant in this case.
 
Must admit I thought it changed in the 16th then found it in the 1st Ed of the 17th.

I think Im guilty of having only read the first line of it in the past. Labels only being required when the presence of the voltage wouldn't normally be expected, I always expect a 3p DB etc to have 400V in it!
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Must be a first that voltage warning labels have been made all but redundant in this case.

Sadly it hasn't stopped them being stuck on everything, everywhere, and rarely straight and level.
 
Sadly it hasn't stopped them being stuck on everything, everywhere, and rarely straight and level.

The problem with warning notices of any kind is if you put up too many, people ignore them all.

Basically if there's electricity involved there's a risk of shock, even animals in fields with electric fences can work that out, they don't need telling.o_O
 
Thanks for the info but it has gone off my question so can I put the house across the 3 phases or does it have to be on the same phase I have 2 x rings upstairs, 2 x upstairs lighting, 1 x smoke circuit, 2 x AC supplies, 3 x down lighting, 2 x downstairs ring all on Rcbo's
 
Thanks for the info but it has gone off my question so can I put the house across the 3 phases or does it have to be on the same phase I have 2 x rings upstairs, 2 x upstairs lighting, 1 x smoke circuit, 2 x AC supplies, 3 x down lighting, 2 x downstairs ring all on Rcbo's

I would spread it over the phases such as to provide the most balanced load, reeling it back in a bit to form logical chunks.

So upstairs ring on one, downstairs ring on two, kitchen on three, ac(1) on one, ac(2) on two

But all smokes on the same (because of interconnection)

Lights on the same (because if you have 2 way on the stairs, you could have 2 different phases in the same switch back box - not many would expect 400v in the same back box!)

Etc.
 

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