Cable break location

[NoSparks]

Breaks in cables often occur. Has anybody any good ideas how to locate the break point?

eg we have an office block in which the cpc is broken. Apart from the obvious ( looking at the fittings), how can we best locate the fault? Is there any method of measuring the length of wire that is intact?

 

[1shortcircuit]

Breaks in cables often occur. Has anybody any good ideas how to locate the break point?

eg we have an office block in which the cpc is broken. Apart from the obvious ( looking at the fittings), how can we best locate the fault? Is there any method of measuring the length of wire that is intact?

I'm no Electrician but I do a lot of work on cars. If I thought there was a break in a particular wire then I would first try to pin point the wire causing the issue and then do a continuity test on it.

It would probably take a number of tests at different points along that wire in order to pin point the break.

 

[ian.settle1]

Use a T.D.R.

 

[Guest123]

I dont think many people would have access to a Time-Domain Reflectometer.

 

[1shortcircuit]

Use a T.D.R.

Like this? Time Domain Reflectometer, ECAD, Cable Testing, PCI-3140R, 1502, 1503 TDR

 

[Mr Mark Sparks]

I dont think many people would have access to a Time-Domain Reflectometer.

dr who has got mine i swapped it for his sonic screwdriver

 

[NoSparks]

A TDR, that looks exactly like what I need but it also looks expensive. I'll investigate further. Thanks for the suggestion.

 

[ian.settle1]

A TDR, that looks exactly like what I need but it also looks expensive. I'll investigate further. Thanks for the suggestion.

If you google TDR hire you will find firms who hire them out.

 

[Soulsurfer]

I dont think many people would have access to a Time-Domain Reflectometer.

O.T.D.R. that'll be ! Used many times installing fibre on old job ;-)

 

[YoungScud]

CableTool TDR Cable Length and Fault Meter: Amazon.co.uk: Electronics

 

[Soulsurfer]

Lol was a joke mate ! don't think an OTDR would find any Rayleigh backscatter on a copper cable ! On a serious note though anyone used a TDR and are they any use for sparks ?

 

[HandySparks]

Lol was a joke mate ! ...

I thought I was a bit slow with jokes, but 6 years...?

 

[telectrix]

don't need that fancy malarky to find my breaks. just clock the nearest pub.

 

[marconi]

Breaks in cables often occur. Has anybody any good ideas how to locate the break point?


eg we have an office block in which the cpc is broken. Apart from the obvious ( looking at the fittings), how can we best locate the fault? Is there any method of measuring the length of wire that is intact?

Could you describe the circuit in the office with the fault a little more? Is it linear (ie a straight end to end run) , branching or a ring?

For a linear or branching circuit my first idea would be to measure the L-cpc potential difference. Where the cpc has continuity to the MET the reading will be full mains potential whereas beyond the break the cpc will be floating at some potential above the MET's potential. This works if no load has metalwork connected to equipotential zone bonded metalwork. Helpful to draw a sketch of the layout of the fittings and if possible draw in the cabling between them either by observation of the cable path or continuity measurement between them, having first disconnected the connections at each fitting.

Or, second idea would be to disconnect L, N and cpc at DB. Connect N and cpc together at DB. Then measure continuity between N and CPC at each fitting. Again, mark up the drawing with the result. Then think about the interconnection(s) between the 'no N-cpc' continuity fittings the remainder and try to trace the section of cabling by disconnecting Ls and Ns at the fittings, joining L to N at a fitting and doing L-N loop continuity measurements at the others.

For ring, disconnect both ends at DB. check continuity of L, N and cpc. If L and N continuous then connect one end's cpc to N at DB and then at each socket measure continuity between N and E. Record results on a drawing. Then disconnect linkage at DB and make a connection between the other end's CPC and N. Mark up drawing and study it.

 

[IzzyS]

He's probably fixed it by now. Or retrained to be a pilot. The original post was 2009.