Help me break into main ring to extend?

[srfeo]

Hi there,

Can you help me plan how to add some sockets to an existing socket which drops down from a ring running between the ceiling and the upstairs floorboards?

The wall where these new sockets will be installed is plaster, so that will involve chasing. Is there any advantage to using a metal or plastic box back for this?

 

[daytona]

chase out all your boxes,then link these up with channels for the cables which you will put in oval or capping.

take two cables from the existing socket and take one to the first new one and one to the spur.

link out all your new stuff so you end up with two at each point.do this in 2.5 .

now the joint at the existing socket.take one leg out of the socket( make sure the neutral and earth are from the same cable as the live) .through crimp this to one of the new cables (you can use 30amp connectors but it will be a bit tight in the backbox).then put the one remaining existing 2.5 with the other new one and second fix the new accesories.earth all the backboxes.

this is assuming the two cables going to the existing socket are part of the ring main

 

[daytona]

use metal boxes 25 mm deep and do thew chases as per your dotted lines to keep inside safe zones

 

[ban-all-sheds]

Move one of the cables going to the existing socket and drop it down the wall to the single, then just wire them through to the existing socket. No crimping, no terminal blocks, no spurs...

Metal backboxes and oval conduit.

 

[srfeo]

Thanks for the advice everyone.

I think that I will try option 1 with the crimping as this will avoid a longer chase up the wall through the ceiling as well as having to cut/lift floorboards and figure out where the wiring goes under the floor.

There should be enough room to have the crimp behind the existing socket and the loop cable run through the new back boxes and behind the front socket panels, no?

What size capping/oval to use for two wires - I don't want to make the chases too large.

 

[ban-all-sheds]

The other option you might want to consider, depending on how visible the existing 2-gang socket is, and its design, is to replace it with 2 singles in a dual accessory box, then you could just loop through the new sockets and back:

I've shown the cables running separately for clarity - in reality you'd put the through the same conduit. (20mm-ish, BTW)

 

[srfeo]

Thanks ban-all-sheds. I saw something like that, but I think that the current socket will be fairly visible, and my wife wants fancy silver sockets so it will be more difficult to fit that.

Hopefully I can get the crimp right in the current two-gang back box. If not I will try the dual-accessory box.

 

[ColJack]

"fancy silver sockets" drastically reduce the amount of free space behind the socket as you lose 6-10mm from the front..

I'd go for 35mm back boxes in that case..

 

[ban-all-sheds]

You will use a proper crimper, won't you, not one of those squeeze'n'hope car electrics jobbies...

 

[srfeo]

Is this a proper crimper?:

http://www.tlc-direct.co.uk/Products/DVDHCR15.html

 

[ban-all-sheds]

It is indeed.

Apologies if you already knew, but some people think you can use these:

 

[srfeo]

Didn't really know - just browsed on TLC until I found one that said for insulated crimps. I'm not sure how big the crimps are - I hope that they fit under the socket front. If not, I guess I will have to buy a deeper back box and do more chasing in.