How to Find the location of a fault - Puzzler

[pevvers]

Thats interesting.

I was going to ask whether anybody actually uses this in fault finding.

Thanks

CH

Yep, I've used it just the once doing initial verification on a nut house wing. Was doing my tests at the board, got 0 on insulation resistance, put it to continuity and got an extremely low reading. Guessed that it was a dead short as a continuity will only pick up a reading when conductors are touching, took the reading, looked up the table for R1+R2 for 2.5 t+e, and divided my reading by it. About 4 metres it worked out as, so measured about 4 metres from the MCB and lo and behold there amongst about 20 other cables in basket was a cable that had been severely twisted to the point that internally it was short to earth. It seemed like a common sense approach at the time, but I still was chuffed when the method worked perfectly!! Now if only the same worked for insulation resistance reading, life would be so much simpler!!

 

[Guest123]

Not if it is T & E it's not.

The questiion states that ALL conductors in this scenario are 2.5mm single conduit cables.

 

[Golden_Boy]

This reminds me of many years ago whilst looking for a fault on a Co-axial underground cable.
We used an ocilloscope thing that put out a very narrow pulse and measured the time it took to reflect from the fault. So having got 35 metres or so we set out with the digger to have a look.
We found no fault at all within about 15 metres both sides of the distance. So we checked again with the kit and got the same result. ( 35 metres ). Then we lifted the examination cover and found 20 metres of cable coiled up in the hole..