Garage supply

[jaguar1]

Should i install the rcd in the main consumer unit in the house , that way it will protect the garage circuits and the supply cable to it.
Or should i just fit an mcb in the main consumer unit and have the rcd in the consumer unit in the garage instead.Thus the supply cable to the garage would not be protected by a rcd

 

[festive]

HI mate, have a search on here in the meantime, been answered a few times i believe, although i must say the search forum facility is pretty kack, comes up with allsorts.

In answer to the RCD protection, one point to consider, if you do run the spur from the RCD side of your CU and something in the shed trips it will trip all RCD protected circuits in your house.
Which may be a trifle uncool.

Burying your SWA cable way below pitch fork depth should be a starter also.

I could say more but feel there's far more qualified people here to fill you in, and i don't want to give you advice unless im 100% sure!

 

[JohnD]

A lot of people will say that if you are working in the outbuilding and trip the RCD, it can be a bit of a pain to have to travel all the way back to the big house to reset it.

I suppose this is more of a problem if it is a workshop and you have substantial grounds. Not a problem I've experienced yet

I share your concern that someone will stick a fork through the buried armoured cable, unlikely though that might be. The fork in contact with the earthed armour will probably trip the MCB at the supply end, but not if you have a neutral/earth fault.

It is better not to put the outbuilding on the main RCD of the CU, as festive says. If you are doubly blessed in both being prosperous and having a Memera CU, then you could easily address it by having a delayed RCBO at the house end and a 30mA RCD at the outbuilding. This is I think a super solution but sadly not cheap.