c/u with rcd in garage

[teddyb]

Moved house. Garage has power and light via a small c/u with 2 fuses. The casing of the c/u is cracked. I have bought a similar sized c/u especially for the garage which has an RCD instead of a simple switch.

There is an integral thick blue cable in the unit - between the neutral block and the RCD itself.

Can you please advise on the where the cables go?
My incoming mains to the RCD?
Circuit lives to the MCBs?
Circuit neutrals to neutral block?
Mains neutral to neutral block??
All earths to earth block.
Do I need to earth the unit itself? If so how/where?

 

[plugwash]

incoming live and neutral go to the two terminals at the top of the RCD, make sure you get them the same way round as the connections leaving the bottom of the RCD

circuit lives go to the top of the MCBs, circuit neutrals to the neutral block

all earths go to the earth block.


if the unit itself is metal then the earth block should already be connected to the body

is this unit fed by armoured cable? if so then things get a little more complicated regarding earthing.

 

[teddyb]

Thanks. I'm still a bit confused though.

Ishall put my incoming mains live and neutral to the top of the RCD; the unit came with its own neutral coming out of the bottom. What other cable will come out beside it?

 

[plugwash]

generally it won't be a cable coming out of the other side of the bottom but instead it will be a metal bar joining to the bottom of the MCBs

 

[teddyb]

Great, that's exactly what I've got!

Thanks very much for your help!