Garage CU

[timegoesby]

There is a CU in the garage with fuses, no RCD and one spare 30A fuse. That is fine. I want to put sockets in the garage and thought of using a garage CU with RCD, and a trip for sockets and one for lights, from Screwfix. No. D-73324. If I connected the garage RCD CU from the

30A fuse on the main CU and ran a ring for sockets off that in the garage, would that be OK? Would I need to just take two 2.5 cables off the spare 30A fuse to the garage RCD CU? Any special regulations for the earth?

TIA

[BigWallop]

Not totally with you here TGB, but I think you mean that the garage is connected to the house, and is not actually a separate building. Is this correct?

How many sockets are you putting in the garage? What things are going to use the sockets for? Are the fuses re-wireable, or are they MCB type breakers?

The 30 Amps fuse could be replaced with a 20 Amps MCB to safely control a radial circuit of two double gang sockets on a length of single 2.5mm csa' T&E cable. If you wish more sockets in the garage, then you could replace the 30 Amps fuse with a 32 Amps MCB to safely control a radial circuit of 10 double gang sockets on a 6 mm csa' cable.

I don't see the need to go installing a new CU for just this area, when it is simpler to use the existing system already supplied. Using separate plug in RCD's from the socket(s) that will need it most during use.