fitting extra sockets

[mikk]

I need to fit (double?) socket in a small room that doesn't have a power point. There is a double socket in the living room directly opposite this room - could I come off this and wire through the cavity wall into the small room? The system uses an MCB if that tells you anything.
I also need to do the same thing in my house, but the wiring is older, and I need to know if it is safe to do so.

 

[Steve]

depends it the socket you intend to spur from is on the ring or not. If it has 2 cables to it, it is safe to take a spur from this. If there is only one, it is almost certainly not ok to take a feed from this. What rating is the MCB?

Are you saying this is not your house? Should you be doing this work in someone else's house, when you have just demonstrated that you clearly have very limited knowledge of electrics? As the last person to touch that circuit in their home, if anything did go wrong with it, it could be blamed on you. Thats how it works i believe.

 

[bpowell555]

Why is it bad to spur off a spur?

 

[Steve]

Why is it bad to spur off a spur?

because the 2.5mm² cable you are using to spur with is only protected by a 30/32A protective device. But it is rated to 27A, so it is acceptable to run one double socket from a spur. Anything more, you will need to protect with a 13A FCU at the source of the spurs and make it a fused spur. Also you can risk overloading one side of the ring with spurs at one point.

 

[bpowell555]

Why is it bad to spur off a spur?

because the 2.5mm² cable you are using to spur with is only protected by a 30/32A protective device. But it is rated to 27A, so it is acceptable to run one double socket from a spur. Anything more, you will need to protect with a 13A FCU at the source of the spurs and make it a fused spur. Also you can risk overloading one side of the ring with spurs at one point.

Cheers crafty.

 

[andy]

If it has 2 cables to it, it is safe to take a spur from this. If there is only one, it is almost certainly not ok to take a feed from this. What rating is the MCB?

make sure that the socket you intend to take the feed from is part of the ring. just bacause it has 2 cables doesnt means its on the ring. it could be a spur with another spur on it. or if its a radial, you can take a branch from anywhere to any length, providing you use the same or higher CSA cable

 

[mikk]

I am fairly sure that it is on the ring. It is one of two double sockets in the living room. At the risk of appearing thick (just wanna be safe) could I confirm this by some kind of meter test?

 

[ban-all-sheds]

Better to ask and risk appearing a fool, than not ask and risk being one...

A couple of tests are needed.

1) With the main switch off remove the wires from the terminals in the CU and check that there is continuity between both lives, both neutrals and both earths - this will confirm that you have a ring and not two radials.

2) With the CU connections restored, but still with power off to the socket circuit - please make very sure of this - a good way is to plug in a table lamp, and turn the MCB off, then back on, and then off again, and check that the lamp does what it should. The reason for the on-again/off-again is to ensure that the bulb didn't fail at just the time you switched the MCB for a different circuit to the one you thought you were doing.

Now remove the cables from the socket, and again check for continuity on all 3 conductors. If you don't get it then that socket is a spur with a spur off of it.