Generator set up

[bigspark17]

Hi guys/gals… just pondering a gennie set up in a domestic that has a double pole changeover switch with 25mm tails in from dno and 25mm out to cu, 4mm cable then supplies the gennie male socket. Two queries i have, should the 4mm t&e have overload protection (all be it would be downstream)? And should there be a supplementary earth spike & 10mm connected to the met?

thanks

 

[pc1966]

The generator output should have OCPD anyway, and as long as nobody does something stupid like make up a 63A plug from a 15kVA generator to 32A or 16A socket feeding your plug & 4mm then I can't see much issue there. If you have any doubts about that sort of thing happening, then putting in a 32A MCB or similar fused-switch would solve it.

But you must have your own Earth provisions for the generator! You cannot assume the supply earth will be present during any sort of fault/outage as the whole supply cable could have been JCB'd. Most generators have 30mA RCDs (if socketed outputs, etc) so the rod below 200 ohm is not going to be too hard to meet but as always if you can safely drive in a 2.4m rod it will be much better.

And yes, I would use 10mm bond for it even if it is not TN-C-S yet, as probably that will happen eventually.

 

[snowhead]

as the whole supply cable could have been JCB'd.

I'd just like to point out that there are other brands of excavators that in the hands of suitably experienced operatives are capable of ripping supply cables out of the ground.?

 

[pc1966]

But you must have your own Earth provisions for the generator!

Just to clarify, it is for the installation when on-generator. It need not be connected directly to the generator and I would simply take it to the MET (as if it were a TT system's rod).