How to wire an extra garage power socket?

10 Jan 2013
Reaction score
United Kingdom
Hello All,

Currently the consumer unit and double socket are on the end wall in my detached garage. I'd like to move the socket to the middle of the garage and install another on the opposite wall. So two sockets opposite each other about 3m from CU.

How would you do it?
Option 1: wire in the first socket and put the other in series with the cable over the joists.
Option 2: use a junction box above CU to split the supply.
Option 3: Put another 2.5mm cable into the CU using the same terminals as the other socket.

I use power tools in my garage. The biggest is a 2kW grinder.


CU from above

Sponsored Links
It doesn't really matter which method you use, although the sockets will be wired in parallel, not series.
It depends on the location of the sockets and how you want to route the cables.

There is no over-current device for the socket in the garage (assuming the socket is not on the 6A MCB) so it must be in the house.
Is the supply run from an MCB in the house consumer unit or just taken from the socket circuit in the house?

Where does the green wire go?
Thanks for your reply. The 6A MCB is for the lights. The detached garage must be on a spur from the lower ring circuit.
Kitchen CU:

The green wire goes to an earthing rod outside.

I'm now off to Screwfix to buy the bits.

As it is supplied from the ring circuit there should be a (switched) Fused Connector Unit at the beginning of the garage circuit.
Is there one?
Sponsored Links
No FCU anywhere, eek! Before you ask, it wasn't me! The garage power was installed sometime before 2004 (red and black wires).
Then, as the protection on the house ring is 32A, if you want more than one socket in the garage, the spur should be protected with either -

an FCU on the supply cable to the garage unit, anywhere will do. like just above the garage CU although in the house would be better,

There are various other options (like relacing the garage CU) but it would be more complicated and expensive.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local