extending a ring main

[Paul Draper]

I wish to extend a ring main into a new conservatory.

I have a socket on the existing ring that I can extend from. Obviously one end of the old ring and 1 new wire from the conservatory will be connected into the original socket. The other pair of wires thus need to be connected together to complete the ring. I know that ideally I would use a 30A junction box to connect them together, but I don't have any spare cable on the old ring. Is it OK to connect the wires inside the existing back box using choclate block or is this a big No No?

If not what are my options?

Thanks

Paul.

[Martin Angove]

I don't think chocolate block would be *dangerous*, but it's not ideal, and I don't think you'd have much luck fitting it all into a standard depth backbox.

Do you *need* the ring in the conservatory, or could you get away with one (double) socket spurred from your existing ring? If you need more than one then a fused spur can be used, but the total loading on all the spur sockets would then need to be kept below 13A (abt 3kW).

There are those here who would recommend crimp connectors, and they would certainly take up less space than a chocolate block and probably be safer, but this would also be a bit "non standard".

The other option is to find out where the ring goes from the existing socket. If it just goes down under a suspended floor (for example), have you thought about doing the wiring under the floor where you'd have a bit more slack to play with?

Don't know if any of that is likely to be of help, but it was worth a shot anyway :-)

Hwyl!

M.

[BillR]

Join the new cable to the old one with proper crimp connectors.

[Andrew McKay]

I recall from my 16th edition course a short time ago that if wires are to be joined and the joint isn't easily accessible (e.g. the joint is buried without an access cover) then a terminal block isn't acceptable.

The reason I happen to remember that little gem is that about 20 years ago I joined some ring main with a heavy-duty terminal block, wrapped it up and then plastered over it.

I know, I shouldn't have done that. But at the time it seemed the right way. And the 16th edition wasn't out then..... :)

Andrew

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[Paul Draper]

A little more info:

I've already run the ring with 4 sockets in the conservatory, and have the ends of the new ring run to the back of the existing socket (not connected yet).

The metal back box is a deep one (about 50 mm) so there is easily room to fit the choccy block behind the socket.

The choccy block I have is rated at 30A.

The choccy block will be accessible by unscrewing the socket.

I don't have spare cable in the existing socket to put a junction box on.

I don't have access to a crimper & crimps (without buying one!)

Given these circumstances does anyone see any problems with using the choccy block?

Thanks Paul.

[Dave Plowman]

None.

[Dave Plowman]

A self tapper into the back of the box? Don't think it matters, though.

[Martin Angove]

Might also be worth putting a bit of tape around it... but if you've stripped the wires correctly (i.e. no bare bits showing which might short on the back box) and given that the screws are sheathed anyway, what the heck? As you've got 50mm to play with, the number of wires and connections doesn't seem too bad either :-) Rather deep for a backbox though - wonder why it was done like this?

Hwyl!

M.