Single Phase Backup Generator to Three Phase Mains Supply?

[chriscapetown]

I have a 6.5kw 220v single phase generator that I want to wire up to supply backup supply to a couple of offices in my house. The mains supply in the house is three phase 220v... Is there a way to wire this up? Something like an isolator/generator switch on one of the phases (as long as the offices are on the same phase)? I don't want to go to the additional expense of purchasing a 3 phase generator or a single to three phase converter but would like backup power into the office circuits. I'm not too concerned about have the entire house on the generator but do need the offices.... Thanks

[David Hansen]

On Mon, 21 Jan 2008 23:27:11 -0800 (PST) someone who may be [e-mail] wrote this:-

I doubt it, especially in the UK. If you are not in the UK perhaps you could say where this house is.

There are ways. However, the confused nature of your description implies to me that you don't have the necessary knowledge of electrical systems to do this safely. There are a number of things which might trap the unwary, for example earthing arrangements.

[Sparks]

Something like this

to one of the phases then to a new consumer unit, supplying power to both offices would work. This would then allow you to power everything on this new consumer unit from the generator in a power cut.

Sparks...

[John Rumm]

Note that you will need to pay careful attention to the earthing arrangement here. If you normally have an earth connection provided by your electricity supplier (i.e. TN-S or TN-C-S), then you will not be able to rely on this when using the generator. This can make switching more complex since you may require alternative circuit protection arrangements.

[Tim..]

Firstly you must have a TT system or at least have it converted to a TT system in order for the protection systems (RCD s etc) to function properly.

Sencondly, depending on how your house / office is distrubuted from the mains 3 phase, it may not be as easy "as that" to supply just the offce from a 1ph generator, inwhich case you will HAVE to have a 3ph machine.

Thirdly, nearly all domestic (i.e under about 15kva 3000rpm) generators are wired with either a single or more likely dual stator (230v or 115v x2) and are unable to be re configured for 3ph output.

Have a spark come out and examine your existing layout and circuit distrubution and advise you from there. Whichever, it will not be a cheap operation.

Tim..

[tony sayer]

In article , Tim.. scribeth thus

You could run a lead from it to some sockets and simply plug what you need to supply of them?. Where they would normally need plugging into the mains.

Otherwise its a changeover switch. A MUST NOT be able to feed the output of the genny back into the mains., Hence these units are break before make changeover but that may well need doing in a rather serious fashion!...