10 meter power cable with broken earth strand.

[alo]

10 meter power cable with broken earth strand.

Is there anyway to find where the break has happened inside the cable?

Thanks

[Tim+]

From a mechanical point of view, it?s most likely to break at the ends closest to the cable grip. Just trim a few inches from one end, test, and if still faulty, trim from the other end. ;-)

Tim

[Fredxx]

Time-domain reflectometer?

I have discovered where an intermittent break is by passing lots of current in the cable.

Swap earth and neutral at both ends and connect to an electric fire. Manipulate the cable until the cable melts in the offending place.

[Tim+]

If the earth has broken anywhere other than the ends then either the cable will show external damage OR, it?s such a naff cable it should be ditched. ;-)

Tim

[williamwright]

Yes but you end up with a lot of short bits.

Bill

[Thomas Prufer]

Do you know what you are doing? If so: Hook the suspect strand to live and go along the cable with a "contactless voltage tester"...

I'd chop both ends off first, 95% the strands break at the end of, or near to the strain relief.

Thomas Prufer

[Ian Jackson]

In message [e-mail], Thomas Prufer [e-mail]> writes

Yes. If you don't want to simply buy another length of cable, those stud/pipe/cable detectors are available from around 20 pounds, eg:

you test with only the suspected wire connected to live, you will probably be able to detect some voltage all along the cable. This is because the broken wire is in close proximity to the other two. However, depending on how far it is to the break, there should be a noticeable drop in level when you reach the break.

[newshound]

+1 to Thomas, personally I'd use a "Volt Stick" rather than one of the wall detector devices. In my experience these will detect the break quite accurately, I would not expect to have problems from capacitative coupling.

[Robin]

earth the other 2 at both ends?

[Chris Green]

Won't one of those (very cheap) wire tracing devices do the job? I have one and it's invaluable for tracing wires in my boat, simply apply the signal to the wire you're wanting to trace at one end and then wave the detector around at the other end to find the wire that produces the loudest signal.

For the OP's problem apply the signal to the ground wire at one end and then move the detector along the wire until there's a sudden noticeable drop in signal.

[Thomas Prufer]

No -- asking for trouble if there is a break in the insulation. And no benefit, the voltstick will work without earth.

Thomas Prufer

[nothanks]

As others have said: check the ends first (pulling on the conductors will sometimes find the problem), then try a volt stick (ground the wires that aren't of interest). If you can't find the break with the above then cut your losses by cutting your cable - at least you now have a good 5m cable ;-)

[Theo]

A good 5m cable, and a good 2.5m cable, a good 1.25m cable, a good 62.5cm cable...

Theo

[Dave Plowman (News]

Try firmly pulling the earth conductor. If it has broken close to one end, it will pull out.

[Scott]

Can you access the entire cable for inspection? Could you work you way along it (with the power off) just wiggling it about to see if you can find a point with added flexibility (only two wires to bend instead of three)?

[Brian Gaff (Sofa]

Unless you can see some damage to the outside, its not easy. I remember on tomorrows World way back a device that put a high frequency audio ton on each wire in turn then you ran a kind of aerial thing down the length and looked for the sudden drop in the signal. Of course to some extent it would coupe to the other wires obviously. It was just above audible range I think and hence would radiate a bit and one assumes the meter on the receiver simply measured the strength,but of course in any electrically noisy place I bet it was totally useless!

The normal places to check are near the end or where there is a strain relief going into a connection.

I suppose you could put a few kv on the earth pins and wait for it to spark and melt something!

Brian

[Brian Gaff (Sofa]

Yes well almost as lethal as my idea. Brian

[Brian Gaff (Sofa]

This will give you a shock or something. When I was a lot younger and foolisher, if that is a word. I had a length of two core and turned it into a garden mower cable. Later on I wanted three core so I put a spike on a fly lead on the plug ends earth, and a spike on the other end, the socket, then just scured both into the soil. I never did manage to kill myself but it seemed like a good idea at the time but as we know now, the earth and Neutral should really be connected together and be at the 0 crossover point. grin. Brian

[Chris Green]

Exactly what I was describing a few posts up in this thread.

Very cheap to buy now and work very well. Electrical noise has little effect because the 'wanted' signal is relatively huge compared with what might be picked up from adjacent noisy devices.

[Brian Gaff (Sofa]

Yes sods law will dictate that it will not be in a place where either part will reach to your job site. I did wonder if the audio tone idea might work but sya instead of audio, its on the long wave band instead, then use a portable radio to find where the signal starts to decline from either end. Brian