Spur from Ring Main

[womble35]

Moved in about two weeks ago and noticed something funny about three extra sockets in the second bedroom. Checked them out today, and I have found that the first socket is spurred from a socket from the ring main, and then the next one is spurred from that one and then the third one is spurred from that, which I know is illegal and completely unsafe.

I want to keep the three extra sockets, as with out them the room would have one. Two if I keep the one spurred from the socket of the ring main, but both the wrong side of the room to be of any use.

I am reasonable good with electrics, spent a few of my holidays working with my uncle as a kid/young adult doing electrics, so I know the basics, but would just like check the idea I have to keep the three extra sockets.

My idea is to convert the first double socket into a dual box, and add a fused spur and 1 gang socket. Then connect the 1 gang to the fused spur, and then spur the next socket (2 gang) from the 1 gang socket. Then spur the final 2 gang socket from the previous 2 gang socket.

I know the best way would be to extend the ring main, but that would require a lot of redecorating. It will be done in the future, but I need to make these safer now.

I have made a diagram of what the circuit looks like now, and my idea to make it safer.

Is a fused spur the best way to do it, and will that many sockets on a fused spur be ok ?

How the current spur is


My idea to add fuse spur.

 

[EFLImpudence]

My idea is to convert the first double socket into a dual box, and add a fused spur and 1 gang socket. Then connect the 1 gang to the fused spur, and then spur the next socket (2 gang) from the 1 gang socket. Then spur the final 2 gang socket from the previous 2 gang socket.

Yes, that is fine.

Just to be clear the FCU will be connected to the ring and all sockets will be on the load side.

Is a fused spur the best way to do it, and will that many sockets on a fused spur be ok ?

Yes, it is all you can do really.

You may have as many sockets after the FCU as you want.

Obviously this will limit the total current used to 13A but this should not be a problem in a bedroom.

 

[womble35]

Thanks for the reply

Just to be clear the FCU will be connected to the ring and all sockets will be on the load side.

Yes they will. The FCU will be connected to the back of the ring main socket, and then all of the sockets will be connected to the load side.

Just taken another look and have just realised that the wrong sized cable has been use as well. The spur from the ring main socket and then the corresponding spurs are 1.5mm T+E

If I remember correctly 1.5mm T+E is rated to 19 amps, so would 1.5mm T+E be safe to use for the sockets connected to the load side of the FCU ?

For the spur to the FCU from the ring main socket I will use 2.5mm T+E, just hoping I can tape the current 1.5mm T+E to some new 2.5mm T+E and pull it carefully through the stud wall. If not I will be decorating sooner than we thought.

 

[vibrobullit407]

1.5mm T&E cable has a max ccc round about 20A depending on reference method. this can go down significantly depending on other factors i.e reference method, grouping, ambient temp and thermal insulation. As you will be protecting with a 13A BS 1361 fuse the correction factor for protective device can be omitted. You will also have to verify that volt drop from the origin of the supply to the extremity of the circuit is no less than 5%.

So answer is if your 1.5mm cable meets the design criteria in regards to the above then it should be fine.

 

[Lectrician]

What else does the ring feed? If it is only the upstairs bedrooms, I would swap the 32amp MCB for a 20amp, at least until you get around to re-jig the wiring when you decorate. No need to worry about the FCU or doing anything to the sockets that way.

 

[scottyboyiow]

Agree with Lectrician if this is possible. If you do decide to go down the FCU route, but do plan on extending these sockets in the ring later on, might aswel use 2.5mm Tw + E to save redoing it later?!

 

[PrenticeBoyofDerry]

The safest option at the moment is to install a FCU where the first spur is off the feed/supply socket outlet as you intend to do. If you do intend to extend the RFC at at a later time, definitely use the same size CSA cable of the existing/original RFC this could be 2.5mm or maybe even 4.00mm.
This will then have provisions in place for the RFC to be extended.
Looking at your diagrams.
If we work clockwise from the CU:
The fourth socket is going to be your supply outlet for the FCU and spurred sockets.
You can then when the time is convenient, remove the link between the third and fourth socket on the RFC, apply this link across the third socket(RFC) and the last spurred socket on FCU, change the FCU and single socket to a double outlet and you have then extended the RFC.

 

[womble35]

Thanks for the replies

What else does the ring feed? If it is only the upstairs bedrooms, I would swap the 32amp MCB for a 20amp, at least until you get around to re-jig the wiring when you decorate. No need to worry about the FCU or doing anything to the sockets that way.

The ring feeds the rest of the upstairs sockets. Downstairs uses a different ring.

The cables in the wall are pretty loose so am 90% certain they will pull through. I will change all of them to 2.5mm (The same as the original) and add the FCU for the time being. Once we get to decorate the room, I will extend the ring, but at least doing it this way will make is safe.

Thanks for all the advice, as I said I am reasonable at electrics, but I always like to get advice/thoughts of an expert before I do anything.

Thank You