Shed power, is this right??

Aok1 · Dec 13, 2009

I am bulding quite a large shed next and i need to get some power in. We currently have a re-wireable fuse board with 30mA rcd on the incoming supply.

I was going to run a 6mm swa from the board to the shed, terminate in a metal box then into a small CU with a few MCB'S.

Just need clarifacation on 2 things -

The supply is TNC-S but the shed will not have any conductive parts so i can export the earth?

No RCD needed in the shed CU? Discrimination problem if i did fit a RCD

Thanks

Deleted member 9648 · Dec 14, 2009

Despite whats been said on here before about outbuildings having to be on a TT there is absolutely no problem with using the TNCS earth for a shed. Only thing I would suggest is that you install a separate switchfuse at the intake for the SWA (not on the RCD) and install an RCD in the shed DB. That will get over the problem of a fault in your shed tripping the whole lot.

Spudnik · Dec 14, 2009

Agreed.

An outbuilding only really needs to be TT if there are services in it.

This saves running a separate 10mm bond back to the MET.

Aok1 · Dec 14, 2009

Thanks , So split the tails and put in a sepeate swich or change the CU for a splitload type would be better?

darleyslad · Dec 14, 2009

Small point of note, I detect from your reply you are apparently more comms then electrical, this project must comply with part P and be certified as such

Aok1 · Dec 14, 2009

darleyslad said:
Small point of note, I detect from your reply you are apparently more comms then electrical, this project must comply with part P and be certified as such

Yes your right mate, but I do have a few years electrical experience. I also have 17th and a disq part p accreditation.
I will be notifying labc and using this for a elecsa assesment.
Thanks alan