Fitting an extra socket in my garage

[Uhtred]

Hi there,

I'm looking for some advice, I have a garage at the bottom of the garden which has a single socket and a light switch (installed together in a double white box on the wall).

I would like a double socket and a light switch (a four way extension isn't suitable because I am trying to use powerline networking which performs badly through these)

Now the building is about 12 years old so the wiring is in good condition, on the trip switch board there is a separate rcb for the garage circuit but looking at the wiring, it seems to be a spur as I can't see a return feed, although there is a thick earth cable which goes back out.

Am I able to install the extra socket legally and safely off this spur?

Let me know if more information is required and thanks for looking

 

[Chri5]

So you have a mcb at the house cu that isolates the circuit to the garage?

What rating does than have?

From here there must be a cable to the garage which goes on to the double back box with the light switch and the single socket?

If the above is correct then you will have a LNE feed from the house. The network over power only needs this and so adding a socket to the garage should be ok.

I have concerns about no rcd on the circuit, and maybe with the load (if the new socket suddenly has a electric fire plugged in).

Could you photo the garage wiring and setup, another of the house cu with the layout and rating for the mcb will allow us to clarify such concerns.

 

[Uhtred]

Hi Chris, thanks for the reply.

So I have taken a few pictures to be sure of everything, but your description sounds correct.

feed from the floor comes up into this switch which isolates both sockets (i'm not really sure what the point of this is?)

https://www.dropbox.com/s/2ksyt1txdhznqz1/2012-08-05 19.50.02.jpg

Here is the feed going down into the socket and switch, with a second wire which goes back up to the light (and a creepy crawly!)

https://www.dropbox.com/s/3hvfw2rom30pido/2012-08-05 19.50.22.jpg

And here is the socket and light switch, with an earth cable which goes down and outside

https://www.dropbox.com/s/8hfe4zget6jej77/2012-08-05 19.50.14.jpg

And here is the 'cu' in the house.

https://www.dropbox.com/s/sh3qcsy9d8ryd2h/2012-08-05 21.07.12.jpg

 

[Chri5]

16 amp at cu, so that suggests a radial run out in 2.5mm cable to the garage.

The fused spur is likely fused at 13 amp and on the load side connects the socket and the light.

Sice everything is controlled by the fused spur running a feed on to a new socket is fine for the existing one.

It will be limited to 13 amp, and has rcd protection via the house cu.

Looks like it was a 16 th ed board. Design wise things have changed a bit, the lights would be on an rcd and having an external circuit (which due to moisture issues is more likely to trip an rcd) on a rcd sharing all the house sockets can be annoying. As in a trip fault situation on the external circuit will pop various circuits in the house. Hope the garden isn't too long

 

[Uhtred]

thanks again. I'll add another double socket on the opposite wall in that case. I have some spare 1.5mm cable, or should I buy some 1.25?

If it started tripping out it would actually do me a favour, i'd have an excuse to dig up the garden and I could install ethernet while I'm there

 

[securespark]

The fused spur is likely fused at 13 amp and on the load side connects the socket and the light.

Unlikely. That would mean the socket would switch off with the light.

A 16A radial does not need any fusing down for the socket, but would for the light, which I assume is switched from the spur adjacent to the socket. In which case, there should be a 3/5A fuse in it.

The switch at the top looks like it is a DP isolation switch for the garage supply.

Should really be a pattress, not a metal box.

 

[securespark]

thanks again. I'll add another double socket on the opposite wall in that case. I have some spare 1.5mm cable, or should I buy some 1.25?

If it started tripping out it would actually do me a favour, i'd have an excuse to dig up the garden and I could install ethernet while I'm there

Stick to 2.5 for the socket.

You don't need an excuse to dig up the garden...

Mind you, if the underground supply is T&E in PVC conduit, that's not right....