Just removing the sheath on a ring main cable in a 3 terminal junction box.

[Always learnin]

Over the years as a DIY-er I've used the old brown 30A circular junction boxes to add spurs to ring mains. I like them as they are strong, secure and visible. I've ALWAYS followed the rules on domestic electricity . Until earlier this year I've been able to check with a cousin who's a "sparky" with any queries but sadly he's no longer with us.

I'm adding a switched, fused spur to a ring main in my bungalow to serve a new outside light. The ring is protected at the Consumer unit with a MCB and a RCD. Yes I know there are other ways of doing this but in my situation this is the best. The ring is in the loft and there's NO slack cable on the ring anywhere near I need there to be. Not even 2 inches. There is however just enough slack to run the ring cable THROUGH the junction box terminals just by removing a small section of the sleeve on each wire. Is this acceptable? Inadvisable? Or just plain against the rules?

Why am I asking? Well I'm considering the copper cable which is ok to compress of course. But what of the risk of severing it and breaking the ring or causing a potential hot spot?

I'm just being cautious by asking, so thank you for your patience and any advice.

 

[westward10]

Strangely enough @Lucien Nunes mentioned this method a few days ago however how would you sleeve the bare earths.

 

[Always learnin]

Strangely enough @Lucien Nunes mentioned this method a few days ago however how would you sleeve the bare earths.

Good point, I hadn't thought of that! See I knew it was a good idea to ask about this on here. Can you provide a link to Lucien's comment, I have tried searching.

So "if" the idea is an acceptable one, how DO I sleeve the bare earth?

 

[westward10]

To sleeve it you would have to cut it. Depending on how the cables run you could cut it, divert to the spur then from the spur back to the ring then it forms part of the ring final.

 

[brianmoooore]

You have to identify the bare earth, and although sleeving is the conventional way of doing this, green/yellow insulating tape is an acceptable alternative.
I'm familiar with the junction boxes the OP is referring to, and back in the day, before sleeving bare earth wires to identify them to the terminally stupid was required, connected hundreds of spurs using exactly the method described.
I would advise against cutting and overlapping the earth wire on an already taut cable, making it even tauter, and the most likely to fail.
Note that this type of junction box is only acceptable if it is accessible.

 

[Always learnin]

You have to identify the bare earth, and although sleeving is the conventional way of doing this, green/yellow insulating tape is an acceptable alternative.
I'm familiar with the junction boxes the OP is referring to, and back in the day, before sleeving bare earth wires to identify them to the terminally stupid was required, connected hundreds of spurs using exactly the method described.
I would advise against cutting and overlapping the earth wire on an already taut cable, making it even tauter, and the most likely to fail.
Note that this type of junction box is only acceptable if it is accessible.

Thank you Brian. I think that's the answer.
I'll go belt and braces and slit open some yellow/green earth sleeving, put that over the bare earth and "close" it with yellow/green insulating tape.
Yes I'm aware these junction boxes have to be accessable and I endeavour to make them visible as well (easy in a loft). I always use an indelible pen as well to write on each cable coming from the junction box, its purpose. You never know when I'm gone it might be useful to somone else or even a sparky in years to come. I know OTT but no harm eh?