Fault finding

[Sammy89]

Hi,

I've got a question on one of my papers that says;

When carrying out an insulation resistance test between live conductors of the socket outlet a short circuit is discovered.

A) describe with the aid of a labelled diagram how you would perform a test to determine the location of the fault within the damaged cable

B) describe the action to be taken to rectify this fault

Any one who could help me out as I can't work out what test u would need to do to find the fault.

Thanks

Sam

 

[ProDave]

Break the ring down into individual legs until you find the leg that's got the short, starting by splitting it in two then splitting again until you find the one leg at fault.

Measure the resistance using the continuity range of your meter.

compare that to the ohms per metre for the cable size in the book and work out how far along the cable the short is likely to be.

In the real world you usually have to replace the whole leg, unless you can find a place to cut into it and make a suitable connection to enable you just to replace the damaged section.

Again in the real world, the short is unlikely to be exactly where you calculate, as it's unlikely the nail or whatever is shorting it is making perfect contact. the measurement really just tells you it must be at least that far along the leg, but may be further away.

 

[NozSpark]

It's called the half split method.

1. Split the circuit in two and test both halfs

2. Split the faulty part in two and test both halfs

3. Repeat 2 until you have found the faulty section of cable or accessory

 

[betty swollocks]

^^^ spot on ^^^

 

[Theorysparky]

in the real world and experience gut feeling works well !!!!

 

[Sammy89]

Cheers all makes sense now

 

[SLIPSHOD & SLAPDASH]

I had a similar fault which i found by the half it & keep halving it method. Pictures here ( you may need to click the pics to enlarge) http://www.talk.electricianforum.co.uk/black-museum-forum/20199-manufacturing-fault-cable.html