Adding Spur with FCU backbox issues - with pics

[DJM]

I have a ring which travels horizontally around the wall. Between sockets I want to fit an FCU to run a socket under a cabinet. For aesthetic and space reasons, I want teh FCU to line up with the other sockets in the ring.

The problem is that due to the (recurring) concrete floor issue, the ring goes out and back through the socket back boxes. How can I fit a new back box in without cutting the return cble. And once cut, how do I reconnect safely and within the regs.

Obviously I can't use choc blocks in the socket back box, but could I crimp joint them inside the box? And if I can, should I just use insulated crimps or do I need to add shrink wrap as well?

Layout below

OK so it's an exageration it's a diagram, but it close to a picture

 

[Taylortwocities]

You could cut slots in the side of the back box and lay your cable thru the box. Once its plastered in it wont move. U need to put protective gromets to protect the cable as it enters and leaves the box.

Alternatively you can put 30A choc block inside the box as it will be acessible or you can crimp. Doesnt need to be sleeved over in the box.

 

[Space cat]

I assume we're talking solid wall here. I would be inclined to chisel a deeper channel for the cable so that it runs behind the new box.

 

[plugwash]

If the entire circuit is in conduit can't you just pull the cable out while you work and pull it back in afterwards?

BTW if you are running a ring like this you REALLY should be spreading the sockets between the two sides, having them all on one side means a very unbalanced ring which is not a good thing.

 

[DJM]

Ring already exists, and I don't know for certain whether it has been balanced across out and back cables. I just drew it that way because cut and paste makes it easier to see.

The ring goes around 3 walls and so would be a bit of a nightmare to pull out and put back.

So it's alright to have choc block and socket in the same box?
I'm tempted to crimp, because it feels like the best engineering solution, but cutting a slot in the back of a box would be the simplest.

This will be checked and signed off so I don't want to fail at a later stage for 5 mins extra work.