OK to extend ring with chocolate in socket box?

As long as it is electrically sound, and the connector block is in an accessible accessory box (ie, not wrapped in PVC tape and hidden under the floor). You might be squeezing it with the connector block in the same accessory box as the socket outlet.

-- JGH

The message

from snipped-for-privacy@arcade.demon.co.uk contains these words:

I could be misremembering but didn't someone say recently that the rule isn't that you can't have more than one spur off a socket but that you can't have more sockets on spurs than there are on the ring. Not something I would want to attempt though. I have enough trouble getting the wires into their holes in the first place even without a spur. :-)

The op could try what I have done in the past when extending ring mains. Repace the double socket with two single sockets in close proximity and wire the extension between them. Don't get the boxes too close together or the second socket will be an interference fit on the side of the first.

But he isn't prposing to do that. He's proposing to split the ring and then insert some more cable and the new socket. Hence the joints.

You can always use a surface box that has space for two separate single sockets. Quite useful if you want extra wiring (and a possible, though arguably not very good way of housing the choc block in this case, by using a blanking plate on one side).

The message from "Bob Eager" contains these words:

But his post started off with:

"I want to add a spur from a socket, but it already has a spur connected."

I read that as the op accepting that more than one spur from the same socket is forbidden. How do you see it?

That's what he wanted to do. But he knew he couldn't.

Thus linking it into the ring.

Why not?

Two spurs from one point on the ring is acceptable (expected loading/balancing of the ring and the number of spurs already taken off the ring may come into play). A spur off a spur is not acceptable.

Adam

Good point. I was assuming he'd be adding a spur to a spur. However, getting four cables in there might be 'challenging'!

The message from "Bob Eager" contains these words:

The wording seemed clear enough to me, as did the problem of inserting all the wires.

Good for you.

The message from "Bob Eager" contains these words:

But not for you. :-)

It bloody well is! I found such a wiring nightmare whilst dry lining a kitchen once. Several junction boxes & bits of cable later I got it sorted.

Your proposed solution may be incorrect.

Regs limit the number of connections in a socket to 3 o 2 connections for the ring legs o 1 connection for 1 socket spur off the ring

You propose a choc-block to keep to 3 connection limit o The choc block would need to be 30/32A

---- two spurs to 2x 1G sockets can draw 2x 13A = 26A

---- two spurs to 2x 2G sockets can draw 4x 13A = 52A*

---- * obviously limited in the latter by 32A ring CPD o The cables feeding the choc block must be 30/32A

---- a spur to 2x 1G sockets is 26A or 1x FTE-2.5mm

---- a spur to 2x 2G sockets is 32A or 2x FTE-2.5mm

---- so link the choc-bloc by FTE-4mm or reroute legs o The choc block & cables take up a lot of space

---- I doubt it would fit even in a 47mm depth box

There are some alternatives.

1. If you only require 13A in total from "two spurs".

a) If your existing socket is 1G (1-gang)... o Fit a Twin-1G metal backbox in place of the 1G socket

---- it is a single metal box with twin-1G fittings

---- separated by a metal plate which you push out o Fit a 1G Socket in the one side

---- into which your 2 ring legs connect o Fit a 1G Fused Outlet (FCU) into other side

---- run 3rd FTE-2.5mm to the socket next to it

---- run as many spurs as you want off this (13A fuse) o Maintains 3-wires into socket & good workmanship

b) If your existing socket is 2G (2-gang)... o Fit a 1G metal backbox next to the socket o Fit a 1G Fused Outlet (FCU) into it

---- run 3rd FTE-2.5mm to the socket next to it

---- run as many spurs as you want off this (13A fuse) o Maintains 3-wires into socket & good workmanship

1. If you require 13A from each spur, 26A total.

o Fit a Twin 1G metal backbox in place of the 1G socket

---- it is a single metal box with twin-1G fittings

---- separated by a metal plate which you push out o Fit a 1G Socket in EACH side of the fitting o Ring leg #1 goes to LH socket, leg #2 to RH socket

---- this separates the original ring o Link the two sockets by FTE-2.5mm

---- this rejoins the ring o Spur #1 off LH socket, Spur #2 off RH socket o Maintains 3-wires into socket & good workmanship

However you may not have sufficient ring leg length.

It can be done similarly with surface mount boxes, but that may be problematic re ring cable length.

You CAN use a 30A junction box under floorboards: o The EXISTING socket become a spur o Your junction box then runs the 2 new spurs as a RING o You would need to link these 2 new spurs as a RING

The problem is accessibility: o Accessibility means an area never subject to furniture o Eg, a landing area, access via hole/floorboard

I would fit a twin-1G box in place of a 1G/2G socket, fit FCU in one side & 1G skt in other. Then run as many spurs as you like off the FCU subject to 13A load limit.

Alternatively extend the ring properly - as a ring.

I think I read your question correctly.

Some socket makes have larger cable capacities than others. Depth of back box makes a big difference too when you have lots of cables or particularly thick cables.

SNIP Interesting. Could you cite the number(s), please? (I can't find it in my old (red-cover) version and I'm too mean to buy a new one until a couple of years after the 17th ed. has been released.)

OSG 16th, p153, Appx8. "A non-fused spur feeds only 1 single/twin/multiple outlet or 1 permanently connected equipment. Such a spur is connected to a circuit at the terminals of a socket outlet or junction box or at the origin of the circuit in the DB".

No regulation is cited, which suggests Guidance. In order to meet the Guidance meens 3 connections.

The OSG guidance can be read as merely existing to prevent a chain of spurs off 1 socket fed by FTE-2.5mm with 32A CPD. It comes down to interpretation - by an Inspector on the day :-)

Frankly, telephone the tech support of the socket maker. If they say it can physically accept the number of wires then you are complying with their instructions of acceptable usage.

They will probably advise a 32-35mm depth backbox though. So the implementation may require physical change anyway.

The TLC Ultimate range sockets have plenty of terminal space for 4 wires...

The other trick to get more backbox depth is to use a spacer:

These surface mount over the sunken backbox and give you an extra 10mm of depth to play with, without changing the appearance of the socket in the way a complete surface mounting pattress would - it still looks flush mounted.

I don't believe there is one. You can have two spurs from the same location if required (point load and balance issues aside)

This does not really have anything to do with the number of spurs at a single connection point, only that a unfused spur should only feed a single socket of flex connection unit etc.

Given 2.5mm^2 is the normal cable of choice, 4 wires ought to be doable on most sockets. Some are very much better designed for this than others. You will note that most junction boxes also have 4 cable entry holes.

or a spacer under the socket.

So you have met my girlfriend.

I cannot comment about the depth of the backbox.

Adam

PS Sorry