Spur off Double Socket.

[Mark328]

I've opened a can of worms here. Any ideas on best way forward?

 

[EFLImpudence]

Not sure where you have got to, but if you put an FCU protecting the existing socket then you can add whatever you want.

 

[Mark328]

Not sure where you have got to, but if you put an FCU protecting the existing socket then you can add whatever you want.

So from existing twin to FCU, then from FCU to new twin. Like this?

 

[JohnW2]

So from existing twin to FCU, then from FCU to new twin. Like this?

The FCU has to be between the ring and the first socket. You can then connect any number of additional sockets to that first one

 

[Mark328]

The FCU has to be between the ring and the first socket. You can then connect any number of additional sockets to that first one

The existing twin only has 1 cable to it, assume its end of a radial circuit. Both the TV and Fireplace obviously come with 3 pin plugs which can be plugged into the existing twin but I just want to avoid having cables trailing from them to the existing twin.

 

[DetlefSchmitz]

So, to do what you want, you need to trace back to find the ring final that all this is connected to. Likely a socket with 3 cables. Then put an FCU between that and the rest of the spur.

 

[DetlefSchmitz]

By the way, the whole 'one spur per socket' came from a statement in the On-Site Guide stating that there shouldn't be more spurs than accessories. 'Electricians' reading this converted it into something they could memorise.

 

[JohnW2]

By the way, the whole 'one spur per socket' came from a statement in the On-Site Guide stating that there shouldn't be more spurs than accessories. 'Electricians' reading this converted it into something they could memorise.

Indeed. It says ...

The total number of fused spurs is unlimited but the number of non-fused spurs is not to exceed the total number of socket-outlets and items of stationary equipment connected directly in the circuit

... which, apart from seeming generally daft, does not really make much sense to me - what is "an item of stationary equipment connected directly in the circuit" if not, effectively, an 'unfused spur'??

As we know, the OSG seem to have invented all sorts of 'rules' of its own, some more bizarre than others. How about this one? ...

As a rule of thumb for rings, unfused spur lengths should not exceed 1/ 8 the cable length from the spur to the furthest point of the ring.

?? -

 

[Mark328]

So, to do what you want, you need to trace back to find the ring final that all this is connected to. Likely a socket with 3 cables. Then put an FCU between that and the rest of the spur.

It's not a ring, the existing twin only has 1 cable to back of it so assuming it's a radial final

 

[JohnW2]

It's not a ring, the existing twin only has 1 cable to back of it so assuming it's a radial final

The other possibility is that it is already a spur from a ring - in which case you would not be able to take further spurs from it.

You need to find out whether or not it is a ring.

 

[Mark328]

The other possibility is that it is already a spur from a ring - in which case you would not be able to take further spurs from it.

You need to find out whether or not it is a ring.

What would be the easiest way. All this is making me think just to plug the appliances in and do with the trailing leads!

 

[JohnW2]

What would be the easiest way. All this is making me think just to plug the appliances in and do with the trailing leads!

To be certain would require'testing'. If you were comfortable to take the front cover off your CU, you could look to see how many wires were going into the top of the MCB or RCBO controlling the circuit ...

If only one wire, it must be a radial
if two wires, it's very probably a ring, but not certainly

 

[Mark328]

To be certain would require'testing'. If you were comfortable to take the front cover off your CU, you could look to see how many wires were going into the top of the MCB or RCBO controlling the circuit ...

If only one wire, it must be a radial
if two wires, it's very probably a ring, but not certainly

It's a bloody old cartridge fuse one. Comfortable with doing though, will take a look. So if it's a ring then the existing twin must be a spur off already then. If it's a radial I'm OK to spur off that twin?

 

[Harry Bloomfield]

What would be the easiest way. All this is making me think just to plug the appliances in and do with the trailing leads!

Unless it all becomes obvious, and certain how it has been wired - then the easy way, seeing as you have so few sockets, is to simply open up all the sockets, part the wires, and test by continuity, what exactly goes where, and how...

It shouldn't be a radial, unless it is wired in 4mm, or the imperial equivalent (7/036 ?).

 

[JohnW2]

It's a bloody old cartridge fuse one. Comfortable with doing though, will take a look.

OK, but only do it if you really are confident and comfortable, and make sure that you don't 'touch anything'!

So if it's a ring then the existing twin must be a spur off already then. If it's a radial I'm OK to spur off that twin?

Yes - but, as I said, looking in the CU alone would not tell you for certain that it's a ring (it could be a radial with a ';branch' originating at the CU),but if there is only one wire connected to the fuse holder for that circuit,then it must be a radial.

What is the 'rating' of the fuse protecting the circuit concerned?

Kind Regards,John