I want to add sockets but....

[dan83590]

How do I know if I am adding into the ring main or an already existing spur without lifting the wooden flooring?

We live in an old building and I have no doubt that over the years the electrical system has been altered. What I want to do is add a extra double socket to each corner of a room. There is 1 double socket per corner at the moment.

Or should I treat each location as if it has already been spurred off the ring by adding a switched 13A fuse?

 

[flameport]

If there are 2 cables in each socket:
Disconnect power, open up the sockets in the room, remove the wires from the socket terminals and check for continuity between the various ends to determine where the cables go.

If the sockets don't have 2 cables, they are not part of the ring, or already have spurs connected.

 

[MisterG]

Hi

If you look at the existing socket you should see two cables connected to the socket if it is part of the main ring and only one if it is a spur.

Hope this helps.

MisterG

 

[dan83590]

I was thinking 'what if more than one socket had been added in a spur'. Only the last socket would have one cable??

 

[MisterG]

Sorry forgot to mention make sure the power is off, but Flameport covered this.

BTW if you see three cables connected to the socket, it means it is part of the ring, but already has a spur.

You can only have one spur from a given socket.

 

[Steve]

Open all 4 sockets up and carefully pull them away from the wall.

If there are two cores in each terminal, and the circuit is protected by a 30 or 32 amp device, the socket is PROBABLY on a ring main and can be spurred from.

If there is only one, and 30 or 32 amp device, its probably a spur and CANNOT be spurred.

If there is only one, and 16 or 20 amp device, its the end of a radial and CAN be spurred.

If there is two, and 16 or 20 amp device, its PROBABLY a radial and CAN be spurred from.

If theres 3 cores you cannot spur.

Im sure people will pick fault with my rough guide. If in doubt come back.

EDIT: too late!

 

[dan83590]

Brill, thanks.

Already checked and every socket has 2 cables to it. I want to double the sockets in the room from 4 to 8. They will not always all be used. Only 4 doubles will be in use at any one time permanantly. Should I change anything else before I add the extra sockets??

 

[MisterG]

I was thinking 'what if more than one socket had been added in a spur'. Only the last socket would have one cable??

You should not have a spur off another spur, but it could be possible if it hasn't been wired properly.

The continuity tests should confirm it is ok, may be safer to get an electrician to check if you are unsure.

 

[dan83590]

Moves fast here. I am happy to do the checks, I just need some acurate guidance.

 

[MisterG]

Brill, thanks.

Already checked and every socket has 2 cables to it. I want to double the sockets in the room from 4 to 8. They will not always all be used. Only 4 doubles will be in use at any one time permanantly. Should I change anything else before I add the extra sockets??

Do you have a modern consumer unit? I think the new regs say if you are not burying the new cable at least 5cm deep then the circuit should be RCD protected.

Also how are you running the cable to the new sockets? There are zones to observe when running the cable to prevent people drilling though cable.

 

[dan83590]

It is an older unit but with trip switches fitted, I think wylex.

The new sockets will be part of a wall that is going to have boards and batons fitted fitted to an existing uneven stone wall. I was going to run the new cables in the void between new plasterboard and existing wall.

 

[MisterG]

It is an older unit but with trip switches fitted, I think wylex.

The new sockets will be part of a wall that is going to have boards and batons fitted fitted to an existing uneven stone wall. I was going to run the new cables in the void between new plasterboard and existing wall.

If all the sockets are at the same height and you run the cable in a straight line from one box to another should be ok.

I saw a good diagram of the zones to observe, I think it may have been in the wikis.

Also are you putting any insulation between the existing wall and the boards? Need to be carefull if you are to make sure the cables don't overheat.

Is the current circuit RCD protected? I don't think the new cable will be at a depth of 5cm. Another option is mechanical protection, but I'm not to sure on the details of that.

 

[dan83590]

Naa, no insulation.

My consumer unit does have circuit breakers but they are inserted into an older style unit, it was the type with fuse wire but we have fitted breakers in their place.

 

[flameport]

An RCD will be required regardless of the cable locations, as these are socket outlets.
Easily sorted by fitting an RCD in a 2 module enclosure next to the existing fusebox.

 

[dan83590]

Ah right.

You just answered my next question. Once the RCD is fitted alongside the retrofitted MCB's will the consumer unit then be to current regs?