Four core Power Cable Short Circuit

[hhhunzai]

Hello Everyone!
Refer to the subject, please guide me in a situation, there is a power cable 25sq. mm, 4 core pvc/pvc non swa buried directly in ground and in some ducts.The cable has damaged anywhere and it shows short circuit between every conductor.I have tested with a uni-T multimeter, it shows almost 2 to 3M ohms resistance between each conductor.The operating voltage is 3 phase, 415volt, 50Hz

Please suggest me a technique to sort this short circuit out, without digging the all area and ducts in ground.Is it possible to locate the exact location of the leakage area?

Your opinions are requested in this regard

 

[hhhunzai]

With 3MΏ at 415 V I’d be inclined to just switch it back in to service. If it holds then OK, if it blows you will have a better (lower) fault reading. You really can’t do fault finding of this type with a multi meter. As to the Wheatstone bridge 3MΏ is to high for it to work.

As you have suggested to switch it back, It was already working but sometimes it makes problems, either due to moisture or or any thing else.
there were two cables with same ratings and cores, one is working with showing infinity resistance and the other is showing 2 to 3M ohms.
I have,t checked with a Megger or cable tester.
You make me understand about Wheatstone method I will try to figure it out by myself.

 

[hhhunzai]

The OP said this is an un-armoured cable so i would guess it would have had some damage all along it caused by pulling it in the duct being a 25mm 4core, there not light.

This cable was working from last three years.
now it is creating troubles, the breaker do not trips every time but two or three times a day. There were two cables with the same specification 25 sq mm, 4core connected to same breaker, and delivering power to a same panel.
One is working now and breaker do not trips after removal of other cable.
Now I have to trace its fault, have to locate the exact location were the problem is.

 

[Knobhead]

A Wheatstone bridge will not work. You don’t have the basic equipment needed for the tests and I seriously doubt the knowledge needed to interpret them if you did. Call a local electrician before you hurt yourself.