Extend Ring or Fused Spur?

[MFRacing]

Hi guys.

Hoping you can clear something up for me…

On the back wall of my (internal – new build house) garage I have a double socket which is on the downstairs ring of the house. So I have two lots of T&E, one coming and one coming out of this socket. I now want to install 2 new double sockets on each side wall of my garage. As far as I understand I can do either:

Spur off the back of the existing double socket into a FCU and then run the new 2 double sockets off this. To do this I would place the FCU below the current double socket and then have 2.5mm T&E coming out of each (left/right) side of the FCU going to each new double socket.

Or

Extend the ring main by taking one of the current set of T&E in the original socket and taking this to the new sockets and back again. But I would have to do this twice as I need the new sockets on either side of the garage (as I can’t take the cables across the garage door opening)

So not sure what would be best to do? If I go with the FCU route all my new sockets are limited to 13a total load? But if I go with extending the ring, I’m not sure if its allowed as I would have to extend the ring twice (one for each side of the garage)? Or do I just take it one side (once it’s gone to one of the new sockets)back through the original socket (without connecting anything) to the other side and then back again and complete the ring?


Thanks guys

 

[PrenticeBoyofDerry]

If you take a FCU spur, then you are limited to 13A maximum on this load!
This may help answer your question are you happy with a maximum 13A load?
Personally I like to extend the circuit, if your cables and sockets are surface mounted this is not too difficult to do.
If you are unhappy having two cables crossing the garage you could extend the ring (that is if it is a ring? two cable present does not confirm this), to one of the additional sockets and spur from that without the need of an FCU.
One point to make, do you have RCD protection existing on this circuit? If not requirements state you do need it on newly installed sockets.

 

[JohnW2]

As far as I understand I can do either:
Spur off the back of the existing double socket into a FCU and then run the new 2 double sockets off this. To do this I would place the FCU below the current double socket and then have 2.5mm T&E coming out of each (left/right) side of the FCU going to each new double socket.
Or
Extend the ring main by taking one of the current set of T&E in the original socket and taking this to the new sockets and back again. But I would have to do this twice as I need the new sockets on either side of the garage (as I can’t take the cables across the garage door opening)

Yes, in principle, those are the two main options.

So not sure what would be best to do? If I go with the FCU route all my new sockets are limited to 13a total load?

That is correct.

But if I go with extending the ring, I’m not sure if its allowed as I would have to extend the ring twice (one for each side of the garage)? Or do I just take it one side (once it’s gone to one of the new sockets)back through the original socket (without connecting anything) to the other side and then back again and complete the ring?

Yes, you would do the latter (or something like it) - the entire circuit must remain a ring.

Extending a ring (i.e. maintaining it as a ring) is always preferable to adding spurs, although the latter can sometimes be more practical/convenient.

There are other possibilities. Some people would frown on taking two unfused spurs off the existing socket (one spur for each new socket) - and there might then be problems in getting four conductors into each of the socket's terminals. Another option would be to extend the ring for just one new socket and then take a (unfused) spur off that to the second new socket - but I can't really see the point in that.

Someone is bound to point out that any new sockets must be RCD protected - is this ring circuit already protected by an RCD in your CU?

Edit: too slow again!

Kind Regards, John

 

[EFLImpudence]

You seem to understand the requirements so whichever is easier.

Some may very well say have each socket on a separate spur from the house socket but I couldn't possibly comment.


Edit - too slow.

 

[JohnW2]

Some may very well say have each socket on a separate spur from the house socket but I couldn't possibly comment.

Indeed - as I wrote "some may frown upon..." However, the '4 conductors in one terminal' thing might be more of an issue.

Edit - too slow.

Even slower than me - PBoD won

Kind Regards, John

 

[JohnW2]

Another option would be to extend the ring for just one new socket and then take a (unfused) spur off that to the second new socket - but I can't really see the point in that.

On reflection, although there would probably be 'no real point' in doing exactly that, it might be convenient to extend the ring to one of the new sockets and then take an unfused spur off the original (not new) socket for the second new socket.

Kind Regards, John

 

[ban-all-sheds]

Can't immediately picture the topology, but always try to extend rather than spur if at all possible. Shouldn't be too difficult in a garage, as the wiring can be on the surface.

But talking of which - do make sure it's protected from physical damage.

 

[Taylortwocities]

is this ring circuit already protected by an RCD in your CU?

The OP did say that it is a

new build house

So we would expect the sockets to compy with the recent regs that mandate RCD protection for socket outlets.

 

[JohnW2]

is this ring circuit already protected by an RCD in your CU? ...

The OP did say that it is a

new build house

... So we would expect the sockets to compy with the recent regs that mandate RCD protection for socket outlets.

Indeed so. As I said, I only mentioned RCD protection because I knew that, if I didn't, someone else would!! As things turned out, that someone else actually 'mentioned it' (and asked the same question that I did) whilst I was still typing my post - so I wonder why you did not direct your comment to him, rather than me?

One point to make, do you have RCD protection existing on this circuit?

Kind Regards, John

 

[PrenticeBoyofDerry]

Indeed new build, so can we safely assume RCD protection is present?
But by all means continue to pick on John and leave me well alone!

 

[MFRacing]

Thanks guys, i'll go from a ring then if thats the preferred option. Lots of more cable though!

Yes fully RCD protected.

Thanks guys

 

[JohnW2]

But by all means continue to pick on John and leave me well alone!

Thank you, kind Sir

Kind Regards, John

 

[Chri5]

Would be better to use plastic trunking for the cable runs, MT2 isn't exactly expensive.

 

[MFRacing]

Yep just ordered the trucking! Thanks

 

[EFLImpudence]

https://youtu.be/w9lmCpIzhFo