Spur question

[andimac101]

Hi

Think this should be a pretty straightforward Q-
I have a twin socket that looks to be on a spur in the lounge and I would like a twin socket in my conservatory (directly the other side of the wall of the socket).

how should I go about doing this?

 

[rossage]

Well if there's 3 lots of cables in the existing socket then it's almost certainly a spur, so another one off of that is a no-no.

You can either incorporate your new conservatory socket(s) into the ring (could be a headache) or find an alternative socket to come off. Make sure you label the CU accordingly. The sockets you've mentioned should also be RCD protected.

 

[Softus]

Well if there's 3 lots of cables in the existing socket then it's almost certainly a spur, so another one off of that is a no-no.

Shirley three lots of cables means that it's been spurred from, not that it is a spur?

 

[rossage]

Yes. And don't call me shirley

 

[Softus]

 

[andimac101]

well actually theres just one cable- I presumed this means that it is a spur from the ring (?)

 

[davy_owen_88]

... or it's the last socket on a radial. What size is the cable and what size fuse/MCB are they connected to?

 

[andimac101]

The cable looks like 2.5mm, and is connected to a 32A MCB- is there some hope yet of spurring off this socket?

 

[davy_owen_88]

The cable looks like 2.5mm, and is connected to a 32A MCB- is there some hope yet of spurring off this socket?

The easiest option in your case would be to fit a 13A FCU before the spurred socket. This allows you to run as many sockets from the load terminals as you like - the downside of this option is the total load through both sockets will be limited to 13A.

A more involved/but better solution would be to fit 2x single sockets in place of the double socket you spurred from and then extend the ring to accommodate the 2 sockets - here is a diagram I drew a while back to explain, the layout in your situation will be different but the method is the same.

Current setup:

New setup (you will extend the ring to accommodate 2 sockets instead of the one shown):

 

[andimac101]

Thanks for that-

Just out of interest, why does fitting the 13A FCU before the spurred socket make this an option, when without the FCU it wouldn't be?

and with only one cable going into the existing socket is this likely then to be the end of a radial circuit? (in which case could I just simply make the conservatory socket the end of the line and the lounge (existing socket) part of the radial?)

 

[davy_owen_88]

Just out of interest, why does fitting the 13A FCU before the spurred socket make this an option, when without the FCU it wouldn't be?

Fitting the FCU before the spurred sockets limits the current that can potentially be drawn through the sockets. One single or one double socket can be spurred from each socket on the ring without fusing down because the maximum current that can be drawn through a double socket is 26A (13A per plug x 2) which is below the current carrying capacity of 2.5mm² twin and earth. If you fit 2 double sockets you could potentially draw more through that length of cable than it is rated to take - hence the need for the FCU.

and with only one cable going into the existing socket is this likely then to be the end of a radial circuit? (in which case could I just simply make the conservatory socket the end of the line and the lounge (existing socket) part of the radial?)

Without testing I can assume, but a 32A MCB with 2.5mm² cables means it is a ring circuit (or atleast should be). if you have a 2.5mm² radial on a 32A breaker you need to get that looked at and reduced to 20A at the most.