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detecting location of underground cable damage

Konara M. Thilakaratna

There is a 4c  armored cable one live cable is  disconnected somewhere around underground area , how to detect the location by mathematically calculate 

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    The alternative way is time domain reflectometry.  You need to be able to disconnect the ends of the cable and then send electrical pulses down it.

    If you know the electrical properties of the cable, it's possible to calculate how far away the broken end is by how long the signal takes to reflect back.

    Phone companies do this to locate breaks in their telephone wires.

  • 0 in reply to Simon Barker

    If you have a meter that measures  capacitance you can read the capacitance of the broken core to the armour and other cores in parallel from both ends,  the capacitance will be proportional to length. This may not be possible if the break has a significant resistance to earth, but then you can put a voltage gradient along the armour, and look at the voltage that appears on the defective section . This only works if there is only one well defined fault, rather than a long damged region.

    Do not overlook the obvious - faults may coincide with new fence posts, or building works, tree roots or other sources of landslip...

    Mike.

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  • 0 in reply to Simon Barker

    If you have a meter that measures  capacitance you can read the capacitance of the broken core to the armour and other cores in parallel from both ends,  the capacitance will be proportional to length. This may not be possible if the break has a significant resistance to earth, but then you can put a voltage gradient along the armour, and look at the voltage that appears on the defective section . This only works if there is only one well defined fault, rather than a long damged region.

    Do not overlook the obvious - faults may coincide with new fence posts, or building works, tree roots or other sources of landslip...

    Mike.

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