DIY Doctor UK DIY Forums

Hi, to give you a quick break down of my situation. I'm working in a converted bungalow that has several generations of wiring and I'm currently trying to add an additional socket (via a junction box) to be located in a loft onto a ring main. Now what I've discovered within the loft are several 2.5mm power cables running the length of the loft and disappears into the floor boards. I know one of these is the ring main though I would like to know which cable is which since there is several ring mains located within the house and I want to ensure I put the socket onto the right ring main.

Now to my question, do any of you know a way to check externally if a cable is truly dead without having a socket to test or cutting into it (so all I have is a middle of the cable). Since I'm planning to switch off each labelled ring main at the breaker and check the cables to try and figure out which is which.

Now I have thought about the possibility of them being spurs but I would check the ring continuity once I have cut into the cable but at least this would help me in knowing which cable to trace.

Thanks in advanced (and a air high five)
David

The simple answer is no, you would not be able to tell if cable is truly dead without a two pole voltage indicator, which require the cable conductors to be exposed.

But, if I was in your situation, this is how I would tackle it.

If you know what circuit you are attempting to use, at the consumer unit.
Isolate all other circuit than the one you wish to use. Then with good quality non-contact voltage pen and a torch, go in to the loft and ID the live cable, this should be the one that has not been isolated. Mark it up, then turn all the electric back on, but turn the one off that you have IDed, then check this is now dead with non-contact stick.
If dead, we can be confident this is the circuit you want. But do not be silly now, go back and completely isolate everything and test again that all cables are dead. Then if you feel brave you can cut into the desired cable, this can then be made off and tested end to end.

Spot on this advice sounds perfect. I would be using this purely as identifying the cables to help me trace which is which, before making any cut to make sure I would just kill the entire house, to be on the safe side.

Thanks again,
D.