Question regarding adding an extra socket to the ring main

[Fiona Reid]

I'm planning to add an extra socket to the ring main in our flat. The exisiting socket is on one side of a solid wall in bedroom 1, the intended location of the new socket will be on the other side of the wall in bedroom 2. I've already replaced several sockets so I know that the exisiting socket is definitely part of the ring and not a spur.

As I intend to put the new socket into the ring main I am imagining that the cables will have the following routing:

A. Exisiting mains cables enter exisiting socket 1 B. New mains cable (and earth) is added to go from existing socket 1 to new socket 2 (on other side of wall) C. New cable (and earth) is used to connect new socket 2 back to current ring main

My questions are:

1. What is the best way to join the cables back together - I've read about crimping, plastic joinning blocks, insulating tape etc. The cables will be beind/inside the brickwork so once the sockets are screwed back on they won't be moved etc.
2. Should I drill two distinct holes though the wall for the cables mentioned in points B and C? or is it safe to have them next to one another? - I guess they are insulated so it's probably ok?

If the above is too complex I'll resort to disconnecting socket 1 and connecting the exisiting wires to the new socket 2 instead. The exisiting socket has a 70kg wardrobe in front of it so I can't get to it.

Many thanks. Fiona

[Bob Mannix]

How will you do (B) above without moving the wardrobe?

If you are going to move the wardrobe, the whole thing is too complicated - if socket 1 is on the ring, socket 2 can be fed by one cable as a spur from socket 1 with a single cable.

[Fiona Reid]

The wardrobe will be moved by parnter and his dad. I've seen the telewest engineer shift it whilst full of clothes so I know it can be done but it's not the sort of task I wish to perform to get to the socket on a daily basis. If we can't budge it then I'll empty it as it was possible to move it (empty) last year when we built it.

There is already a spur connected to the ring so I need to include the new socket on the ring and not as a second spur.

Fiona

complicated -

[Christian McArdle]

Don't bother putting it on the ring properly. Run it as a spur. If the original socket is definitely not a spur and has only two cables into it, just run a short length of 2.5mm T&E from the existing socket to the new one.

I don't get this. You need access to the socket to do your original plan too, so you'll have to either move the wardrobe, or intercept the cable further down the wall and install a junction box (usually in the form of an additional double socket!) or crimps.

i.e.

new socket wanted -> ****

--------------------------------------- WALL

--------------------------------------- ...****......................... ****

----------------------.-.------------- WALL new cable-> . .

[Christian McArdle]

You can have as many spurs as you have accessories on the ring. You may only take one spur off each individual accessory. (i.e. you can't take two spurs off a single socket).

Christian.

[usenet]

You can have more than one spur on a ring. You just can't have more than one (double) socket on each spur. There is also a nominal limit on the total number of spurs allowed, there shouldn't be more spurs that there are sockets on the ring.

So the simple (and perfectly acceptable) solution for you is to wire the new socket as a spur.

[Kev Pearce]

complicated -

However if you are ever likely to want to add further sockets in the second bedroom then overloading problems could occur.

If it is possible, then the best way to avoid this future problem is to proceed as you originally described, but instead of trying to connect back into the ring (step c), work out where it goes and decide if it is practical to pull a new length of cabling through so that your new socket is cleanly linked to the next socket in the ring.

Danger is that if you 'loose' the cable whilst pulling through then things start to get more difficult so ensure that you take all precautions for a good mechanical lock between the new and old cables (eg folded back and twisted, with a dab of solder to stop it coming undone) and some tape wrapping to ensure no sharp edges to get snagged !

No reason why cables B and C shouldn't pass through one hole on brickwork, just ensure edges are protected or rounded to stop the sleeving from getting scuffed.

Good Luck

Kevin

[Andrew Gabriel]

I suspect the thinking is that a ring circuit is usually initially installed with no spurs (or very few at most). If you start reaching the point where you have as many spurs as original outlets, then you should be rewiring the ring to meet your current requirements, and not continuously extending one which obviously falls far short of your current requirements.

Strictly, this is just a recommendation in the On-site guide. It was removed from the wiring regs, IIRC when 16th edition first came out.

There is no such restriction. In practice, getting 4 wires into a connection on the back of a socket can be a challenge, but it's not impossible given a good quality socket and a deep back box for the extra wires.

You should avoid adding large loads near one end of a ring circuit. In this case, take the spur from the ring circuit fuseway.

[Andy Wade]

Yes you can (subject to consideration of likely loading and distribution of current in the ring).

[Christian McArdle]

OK, but you might need to do calculations! I presumed that the recommendation to do this was to prevent loads of spurs being taken off the same area of a ring causing lopsidedness. If you don't follow the recommendation, you still have to find an alternative method of not doing so.

Christian.

[usenet]

I don't think this is actually in the regulations is it, it's sort of grown up from the "no more spurs than sockets on the ring" rule. It can be quite difficult to get four sets of wire into one socket back box in a decent fashion though.