Extending a Ring Circuit

[Jupiter01]

I’ve got lots of ring circuit cables passing through the loft. I want to cut into one of these to drop down into the bedroom for a new socket.

I will check that it’s on the upstairs ring and safely isolate before doing the work.

Can I use one wago box and have 2 x 2.5mm T&E coming out of it to feed the new socket or do I have two have one Wago box for each leg of the ring?

Thanks in advance.

 

[Taylortwocities]

One box, one length of 2.5mm cable to the new socket.
is the ring circuit protected by a 30mA RCD?

 

[EFLImpudence]

Popcorn time.

 

[flameport]

Can I use one wago box and have 2 x 2.5mm T&E coming out of it to feed the new socket or do I have two have one Wago box for each leg of the ring?

A box is exactly that - a box with nothing in it. The quantity of boxes is mostly unrelated to the circuit configuration.

To extend the ring you will need 6 two-port connectors, 3 for each cable.
Cut existing cable, extend both cut ends to the new socket.
All 6 connectors can go into the same box.

To add an unfused spur you need 3 three-port connectors.
Cut existing cable, add 3rd cable to the new socket. Connect all 3 ends together.
The connectors go into a box.

 

[AndyPRK]

Lucky you having socket ring cables in the loft.

If it’s only a double socket you can spur off the cable.

Although against modern regs, I would get a nice old round 30a junction box. Cheaper than wago.

Don’t cut the ring cable. Use a blade to cut down the cable where the earth is.

Remove grub screws from junction (careful not to loose)
Remove the coloured insulation off the cables just where they need to go into the terminals and fit in.
Then connect in the new cable.

This does not reduce the ring resistance and is actually easier to do

 

[crystal ball]

Lucky you having socket ring cables in the loft.

If it’s only a double socket you can spur off the cable.

Although against modern regs, I would get a nice old 30a junction boxes. Cheaper than wago.

Don’t cut the ring cable. Use a blade to cut down the cable where the earth is.

Remove grub screws from junction (careful not to loose)
Remove the coloured insulation off the cables just where they need to go into the terminals and fit in.
Then connect in the new cable.

This does not reduce the rings resistance and is actually easier to do

How would you sleeve the CPC?

 

[AndyPRK]

You don’t. Better to have it continuous.

Diyer unlikely to have any sleeve anyway. There is no slack cable for it to move and touch anything.

You can sleeve the new cable if it makes you happier.

 

[Jupiter01]

The reason I was asking about 1 or 2 Wago boxes was that I thought it would be preferable to see the two legs of the ring separated throughout, rather than them merging into a single Wago box.

Based on the above, I will use a single Wago box, how do I then decide whether I extend the ring by taking two separate legs to the new socket or do I take a single cable (unfused spur). I was inclined to go with the ring extension and having twi new legs out of the Wago box.

 

[Taylortwocities]

Pointless taking two cables to a single socket. Unless you have plans for more sockets later.

 

[pete01]

One junction box and one spur cable, use 4mm incase you need another socket one day.

 

[ericmark]

There is a limit to the length of cable used in a ring final. Starting from scratch easy enough, allowed 106 meter so if used less than a role OK, but to extend existing job one is to work out how much cable has already been used.

The diagram in the book shows what is allowed. However my meter measures in 0.1Ω increments, and really needs to be on 0.01Ω increments, but unless right on the edge then my meter will do. Better than having no meter.

In the main DIY we cross our fingers, and don't test to the degree we should, even if I drive through the village at 25 MPH, that does not make it OK, we all know the speed limit is 20 MPH, and if instructing some one I would tell them 20 MPH, same with electrics we may not always follow the rules our selves, but when telling some one else how to do the job, we should be saying how RCD testing is required etc.