Cable tracing

[Paul Matthews]

I have recently moved house, and have a socket that does not work. I have had the socket off and metered it, and the wires are dead.

There are three sets of wires to the back, so it *looks* like it is part of a ring and has a spur off it, but I cannot find anything else that does not work.

I have taken the sockets off all the upstairs (it is an upstairs socket) and all have two wires in, so look like the ring is intact upstairs, so it looks like I need to follow where the wires go. I don't particulalrly want to start pulling the floors up to follow a wire (god knows how much I would need to lift!) as the floors are chipboard flooring.

Having a look I can see tools like the fluke 2042 that injects a signal to be traced, but cost is prohibitive to just buy one.

Does anyone have any suggestions on cheaper alternatives, or even DIY solutions? any ideas where I might hire such a thing (Manchester/Warrington/Preston/Wigan/Bolton areas)? HSS only seem to do a huge thing...

Thanks, Paul.

[Stuart Kenny]

Hi Paul

I would suggest that a cheap and reliable way of proceeding requires only a cheap multimeter (AC voltage and resistance functions) and some time.

Disconnect the ring-main tails from the distribution board (consumer unit) and pull out ALL plugs in the house. If you suspect that anything is a spur off the mains circuit then switch it off too (e.g. cooker hoods, central heating unless it's on an individual breaker). Verify that all the sockets are dead. Next check that there is continuity between the tails that you've just disconnected at the CU. Obviously you're only expecting N to N and L to L resistance to be an Ohm or lower (taking account the contact resistance of the meter leads). Any conductivity between N and L means that you've still got a load connected to the circuit somewhere.

If someone has been creative with wiring in the past then you'll not see N to N and L to L conductivity. This is commonly because a span of T&E has developed a N to L conduction path and someone has isolated that cable at the expense of breaking the ring.

Lastly, start unscrewing all of the plug sockets and look for cable ends that have been disconnected, insulated or cropped short. By isolating a span of cable and shorting one set of ends together, you'll be able to tell the other end as it's measurable as a short. If the short can be measured in more than one place then you haven't isolated both ends of the cable yet.

Do this, map the socket to socket connectivity and you have a sure-fire way of knowing what is wired to what.

regards Stuart

[Paul Matthews]

Given I would be working on my own, a battery and buzzer would probably be used!

I have considered that, but am concerned about the time taken to go though that

- I am probably look at a full day, escpecially as some sockets are behind cupboards. I don't mind pulling a cupboard if I know that is where I need to connect, but it is an awful lot of work to do as an excercise - I'd probablly need to get rid of the wife and children for a weekend.

Mt brother will be replacing the CU for me in a coup[le of weeks, so the L-L checks would be ideal then.

Thanks, for the suggestion, P.