Domestic 2 phase system and additional single phase supply.

Question

Hi everyone, a domestic refurb has an existing 2phase supply. The DNO cut-out is arranged like a standard PME system. Is it reasonable to use the same earth terminal for both phases. I guess this is the same as what would be standard for a 3phase system, only in this instance 2phases. Additionally our client has applied for another single phase supply that is to enter site at another location, therefore 2 supplies onto one site. The DNO seem happy with this though I find it unusual as commercial projects do not seem to like two PME supplies onto one site?

AJJewsbury · Accepted Answer

not seem to like two PME supplies onto one site 
 
 Depends what's meant by "site" - if it's to two separate buildings situated well apart but just happen to be on the same farm for instance, that's likely to be fine. If it's two supplies into the same big building with lots of shared metallic pipework or structural steel, that's much more likely to be a problem. It's the somewhere in between that gets tricky... 
 Some DNOs do have ways around this sort of thing - e.g. having one common PME point outside the site, and running PE and N separately from there to each intake position. It's still PME, but avoids the worst of the diverted N currents problems. 
 - Andy.

mapj1 · Answer

Any scope to ignore both company electrodes and make it 'TT' ? Eliminates the other problem with the pool in one stroke. 
 Mike.

Domestic 2 phase system and additional single phase supply.

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