Insulation Resistance test question?

[LittleHelper]

Hi guys,
I have what may seem a basic question.
If a cable has been skinned at some point along the circuit would an IR test pick that up in the readings?

Many thanks

 

[westward10]

What do you mean by skinned, the sheath, insulation or both.

 

[static zap]

Rodent damage ?

 

[KEV 1 N]

No, unless it’s touching another cable (if also damaged, exposing copper) or earthed metal containment.

 

[Octopus]

Why the question? College work?

 

[LittleHelper]

Thanks for response guys. The main reason for the question was I got into an debate with someone at work as I was doing an IR test and the meter was climbing slowly but climbing never the less. He said there is a fault on the newly installed circuit where a cable may have been nicked/burned when pulling them in ( was effortless to run no chance of burning). I said to him more than likely the environment we are in is a little damp & cold and the plastering has recently been done so residue moisture in the air and at terminations may be making the meter climb slowly. Which I still believe to be the case. Also there are no loads as we are at the beginning of second fix of accessories for a load reading to be causing test effect. The meter is in good order and I have retested a length of cable with perfect results. We powered up the circuit and it held fine with rcbo in place. but he believes there is a fault.


Thanks again for feedback guys!!

 

[Des 56]

I tend to agree with what "you know" is more than likely LH

 

[KEV 1 N]

What sort of cable was it?

 

[LittleHelper]

T&E KEV 1 N

 

[KEV 1 N]

What was the highest reading?

 

[telectrix]

seems like damp. tell your mate to stop being an arse.

 

[Gavin John Hyde]

Agree with your thoughts OP, often see it when IR testing in old or cold properties, the readings progressively rise the longer you leave the probes connected as it warms the cable a bit. within 30 secs it can go up a few hundred Mohms. So unless you have a clear short i wouldnt worry too much,

 

[PEG]

Agree with your thoughts OP, often see it when IR testing in old or cold properties, the readings progressively rise the longer you leave the probes connected as it warms the cable a bit. within 30 secs it can go up a few hundred Mohms. So unless you have a clear short i wouldnt worry too much,

Warms the cable? Tesla batteries in that MFT?