It would be, but it would involve a lot of unnecessary extra work (to widen the hole for the back box) if, as is likely, the existing socket is mounted on a back box.Why ? , as far as I understand that method is compliant with the regulations.
I agree widening the hole by a few millimeters is necessary but it avoids the need to squeeze a connector into the box behind the socket.
Getting a suitably rated connector in the existing back box may not be possible if it is a shallow box. Widening a far easier than making the hole deeper to get a deeper back box in.
Fair enough - although I have to say that there is really very little difference between the 'usability' of 2.5mm² and 4mm² cable - the stiffness one might gain by the larger CSA of 4mm² is largely offset by the fact that its conductors are stranded, not solid.That all makes sense to me. I have flat screw less sockets so the ring main extension will in all likelihood work better for me as 4mm2 cable to create a spur will be very stiff and most probably bend the socket outward in the middle.
Avoidance of joints is, where possible always desirable. However, what you propose could represent a fair bit of extra work (the existing sockets are quite probably fed from under the floorboards), so I'm not sure that I would personally bother (unless the floorboards were going to have to come up for some other reason).My only question is if I am able to replace the cable going to the next socket rather than having a joint can I run the unbroken cable through the existing sockets back box? I tried to ask this earlier but I don't think I was clear enough. Same wiring as in your diagram but no joint which is my preference and yours by the sound of it. No guarantee this will be possible until I start exploring I would just like to know the options before I start.
Fair enough - although I have to say that there is really very little difference between the 'usability' of 2.5mm² and 4mm² cable - the stiffness one might gain by the larger CSA of 4mm² is largely offset by the fact that its conductors are stranded, not solid.
Kind Regards, John
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