Garage alteration

[PAD66]

Hi All
Installing a 2nd CU in a garage, the garage is currently fed by a 4mm t&e cable (overhead) direct from the cu in the house protected by a 32A mcb. I've been asked to replace this with a SWA to go under the new path, I intend to install a Wylex board with a 63A 30ma RCD incomer, 6A mcb lights, 16A mcb socket. The bit I'm unsure about is the customer requires a further feed to a second detached garage, I intend to run about 25mtrs of 4mm swa from the new cu to a double pole switch then a 2 gang socket and then a fcu and switch for a florescent fitting. The customer has said he might want to add an electric gate which would be attached to this garage. Would it be OK to protect this circuit with a 20A mcb or should I fit a 32A in case of the additional loading at a later date

Regards
PAD66

 

[telectrix]

fit a 20A. you can always upgrade later. better still, use 6mm instead of 4mm, as you are already installing 6mm from the house. don't forget that if either outbuilding has extrasneous metalwork and it's PME, you'll need to run in 10mm bonding.

 

[Spoon]

Im presuming the main CU in the house doesn't have a RCD?
So you intend to run the power from the new CU to the second garage. Can't you just run a separate cable back to the house CU? That way if the new CU trips it doesnt take out the second garage.. I suppose it all depends on the layout of the buildings...

 

[AndyL]

I would say a 20A CB to the second garage, as you only have a 32A at the origin anyway. This will give you some discrimination. I'm sure the electric gate wont add too much to the loadings

 

[PAD66]

Thanks for the replies, will fit the 20A MCB.