Spur off Double Socket.

[Mark328]

Hi All,

I have installed a single socket behind a wall mounted TV which is fed from a nearby original double socket with 2.5mm T&E.

I installed the TV and I then drilled through the side of the redundant chimney breast and run the 2.5mm T & E through external trunking at floor level and then vertically up into the bottom of the surface mounted double socket.

I have a new electric fire place coming soon and whilst I know I can simply plug this in, I wondered if I could use the same trunking path and also hardwire this into the double socket.

I would put the fireplace cable through a fused connection unit first, and then onto the double socket.

So in theory, can I have the single socket spur (TV plug) and the FCU coming off the double socket? Both the TV and the fireplace would of been plugged into said double socket via their plugs anyway but wanted to avoid having plugs and leads everywhere.

The double socket would only ever have a phone charger or hoover plugged in if that helps.

 

[Ragnar_AT]

Yes, you can have two or more spurs connected to the ring at the same point. Things might get a bit crowded behind the socket with four cables though.

 

[Mark328]

I've just had a thought. The double socket is either an end radial or potentially a spur off. (only L,N & E at rear of this socket), How can I tell if this is a spur off somewhere else or end radial? If it's a spur off somewhere else this would obviously mean my new single socket spur off might be off a spur which is a NO!

 

[Ragnar_AT]

Look at the circuit breaker. A 2.5 mm2 radial can’t be on more than 20 amps, if there‘s a 30 or 32 A fuse or MCB the circuit is either a 4 mm2 radial or a ring.

If 20 A or less, anything you add is an addition to the radial circuit rather than a spur and therefore much less of a headache.

 

[Mark328]

It's an old house and has the old CU with a 30A cartridge fuse for the sockets. I know this as the fuse went and had to buy (Wylex 30A).

Problem is I suppose is what SHOULD the fuse amperage be, it was a 30A so I replaced with a 30A.

It is a very small 2 up, 2 down terraced house with only 2 double sockets in the living room and 2 doubles in the kitchen. The CU is in the living room on the front facing wall, i.e 2 double sockets in kitchen are furthest away from CU.

I think I need to take a good look at the CU also to see if there is a separate fuse for up/down sockets and up/down lights.

 

[Harry Bloomfield]

I would put the fireplace cable through a fused connection unit first, and then onto the double socket.

You are not allowed to have two spurs, from a single point on the ring. You could connect a fused spur to the twin socket, then have as many sockets as you like. Alternatively, you could convert your first spur, so it is actually on the ring, then add a spur from that

 

[Mark328]

You are not allowed to have two spurs, from a single point on the ring. You could connect a fused spur to the twin socket, then have as many sockets as you like. Alternatively, you could convert your first spur, so it is actually on the ring, then add a spur from that

So in theory, from the original double socket, come off that with a loading to a single FCU (for the fireplace) but I can't have single socket connected to that FCU aswell so what would power my new (behind tv) socket?

Just to be clear, at the moment I just have the new single socket spurred off the double. No FCU or even fireplace yet.

 

[Mark328]

Might just plug both appliances into the double socket if can't be done efficiently/safely. There's only 1.5m between both appliances and the double socket, just wanted cable free zone!

 

[Mark328]

Eureka moment?.

From existing twin socket on wrong wall (wrong as in would mean trailing cables) to an FCU, from FCU to new twin socket on side of chimney breast and then plug fireplace and tv into said new twin.

New twin protected by the FCU which in turn protects the circuit that the original twin is on now.

I don't mind 2 plugs, but not where the socket currently is!

 

[sparkwright]

If the existing socket has just one cable, and is a spur from a 30 amp ring circuit, I would;
Fit an unswitched FCU BEFORE the existing socket.

So the new unswitched FCU would therefore serve the original existing socket, a switched FCU serving the electric fire only, and the TV socket.

The unswitched spur can serve an unlimited amout of sockets and FCUs - assuming the total load doesn't exceed 13 amps.

 

[Mark328]

If the existing socket has just one cable, and is a spur from a 30 amp ring circuit, I would;
Fit an unswitched FCU BEFORE the existing socket.

So the new unswitched FCU would therefore serve the original existing socket, a switched FCU serving the electric fire only, and the TV socket.

The unswitched spur can serve an unlimited amout of sockets and FCUs - assuming the total load doesn't exceed 13 amps.

I wouldnt have a clue where this original twin is fed from (to put in the unswitched before it)!

I've realised aswell that the new fireplace (if like the old one) will have 2 power requirements (1 for lights, 1 for the electric fire). On the old fireplace it had a double socket within the rear of the carcass with a flex out of with 1 plug. Not sure how that effects things.

The annoying thing here is that the TV and fireplace could easily be plugged in to a twin but the existing twin is on the wrong wall.

Thanks

 

[JohnW2]

You are not allowed to have two spurs, from a single point on the ring.

There is no regulatory restriction on how many unfused spurs can originate from one point on the ring, the limit being due to the practicalities of getting multiple cables into terminals and backbox - which, in practice, means that two spurs is the most one can sensibly originate from one point' (e.g. socket).

However, each of the unfused spurs is (per guidance in the regs) limited to just one (single or double) socket.

 

[PrenticeBoyofDerry]

If the circuit is Ring Final Circuit (general assumption would be 32A Breaker and 2x2.5mm cable connected for RFC at the DB) , you can only take one unfused spur from the feed/supply socket. You cannot have multiple unfused spurs. If the circuit is a radial is radial (32A Breaker 1x4.00mm Cable or 20A/16A 1x2.5mm cable at the DB). Then you can extend the radial without needs of a FCU (fused connection unit, using the cable size suitable for breaker size. If you are spurring or extending from a RFC (ring final circuit) your options are either, extend the circuit correctly by keeping it a RFC (two cable loop extension) or one unfused spur only, this can be a single/double socket. Or down fuse at intersection of feed/supply socket via 13amp FCU, thereafter multiple addition can be installed.
Confirmation of RFC would be required prior to and after work. Any new work requires RCD/RCBO protection. Please use the guidance in BS7671.

 

[davelx]

In which regulation of BS7671 is the above stated? Reg.number please, not guidance from an appendix which is only advisory.

 

[Harry Bloomfield]

There is no regulatory restriction on how many unfused spurs can originate from one point on the ring, the limit being due to the practicalities of getting multiple cables into terminals and backbox - which, in practice, means that two spurs is the most one can sensibly originate from one point' (e.g. socket).

My understanding has always been - only one unfused spur, from any point on the ring - as per @PrenticeBoyofDerry post.
.