Adding sockets

[grahammm]

Hi,

Currently I have 3 single sockets in the lounge, not particularly helpful with TV, router, printer (odd I know), XBOX, set top box etc.

So I'm looking to add 3 double sockets.

Before I start, I just want to check that my understanding is correct.

1) Adding sockets into a ring main requires no planning permission / notification (it's not a kitchen or bathroom).

2) The "better" way would be to extend the ring main as you can only add 1 spur to each socket and these sockets are wired behind the plaster so makes this tricky.

3) There is no limit on junction boxes, so I propose to cut the cable in 2. Wire one end of the existing cable into the junction box, then from that junction box to new socket1, then wire from socket 1 to socket 2, then socket 2 to socket 3 and then join up new circuit with the existing circuit by another junction box.

4) Junction boxes can;t be left hanging, so need mounting. Is mounting to a roof joist acceptable?


So that's how I plan to do it. The issue is there are 3 circuits coming out of the fuse box and it's not clear which one is which. I propose turning it all off, cutting one of the cables, sheathing it and taping the 3 connections on both bits of the cut. I can then turn the electricity back on and work out which circuit it is I've cut - once I've done that, I could use a junction box to rejoin them and write on it which circuit for future use. The 3 circuits are sockets, lights and kitchen sockets. I can probably eliminate the kitchen sockets by where the cables go so should be 50:50 chance!

My worry is that I read the maximum distance is 100m per circuit and I'm worried this may take it over. I live in a 2bed flat so it's not huge but I have no idea how long the current cabling is!!!

Any comments much appreciated!

Thanks

Graham

 

[JohnD]

there are 3 circuits coming out of the fuse box and it's not clear which one is which.

do not start work until you are completely certain.

do not cut wires and tape the ends.

draw a plan of the house on a large piece of paper and draw all the existing sockets on it.

test all the sockets to verify that they all work.

turn off one of the MCBs. Test all the sockets again. The ones that are now dead, write "MCB1" on them on your plan.

Turn the first MCB back on. turn off another of the MCBs. Test all the sockets again (including the ones that were dead before). The ones that are now dead, write "MCB2" on them on your plan.

Repeat for MCB3.

Now turn off all three MCBs. Test all your sockets again. Go round the entire house looking for anything that has stopped working, including boiler, extractor, lights, cooker, immersion heater. If you find anything, work out which MCB controls it and mark it on your plan.

In the event of a bad installation, you might find something that works until TWO MCBs are turned off. This is a defect that you will have to investigate and correct.

In your position, I would change the three existing single sockets to doubles, for a start, and probably run another double as an unfused spur from each, chasing horizontally along the wall. In a living room, a double socket near each corner, and in the centre of the long walls, is reasonable. That will give you six double sockets in the room, which is reasonable unless it is particularly big.

You can run your TV, music, and PC apparatus off multiway short extensions.

There is no need to use junction boxes.

Do you mean your walls are drylined with plasterboard with a gap and then brickwork? How old is the house?

I don't know why you talk of putting things in the loft. Is the floor concrete?

 

[ericmark]

1) You need to ensure all new sockets are RCD protected.
2) Any buried cable less than 50mm deep unless special expensive cable is used.
3) You need to inspect and test very carefully to ensure the ring is not broken.
4) Correct one only socket on a un-fused spur but you can add as many as you want to a fused spur.

To extend a ring normally one would fit either two single sockets in a twin back box or two single grid type sockets which only require a double back box. But much depends where you want the extra sockets.

The big problem with DIY is the testing and inspecting. Because of this problem using FCU is popular for the DIY guy and where RCD is not already fitted a RCD FCU can also get around that problem.

Major problem is to work out what you already have. It would be nice if no one ever broke the rules. But that is not the case.

In an office block, i.e. all work done by electricians no DIY, I found a B32 MCB with 4mm² cable feeding a row of sockets until in one room I found two socket boxes next to each other and some 2.5mm² cable feeding a further 4 sockets with returned to the second box and from there in 4mm² it fed another 8 sockets in two more rooms.

Clearly the electrician had thought he was working on a ring final not a radial and had thought he was extending that ring. Clearly he did not test it first or he would have realised his mistake.

He was cutting corners but so do many and so testing is always required. I was lucky to find the error before adding even more sockets. I had ordered up 4mm² ready but my testing showed odd results between two sockets when using a loop impedance tester so I investigated further.

In a house it's anyone's guess as to what you have. So step one is always to inspect and test only after that do you design how extras are to be added.