IR reading

[Richard100762]

I was called to a tripped rcbo on a lighting circuit. Using my megger 1721 I checked continuity between N and E but noticed an induced voltage of around 15V. Same across L and E. When I did IR checks the readings fluctuated between 1 and 90M and eventually the meter showed ‘Error’ and had to be recycled to work again. Put it all back together and it stayed on. Went away an hour later was called to say it tripped again.

 

[newfutile]

Sounds like water ingress to me,any outside lights or steam from showers or cooking?

 

[Richard100762]

Sounds like water ingress to me,any outside lights or steam from showers or cooking?

There aren’t any outside electrics on the circuit. Could the induced voltage be a clue.

 

[Bluetit]

I would start breaking it down until you get a stable IR and go from there myself.

 

[Richard100762]

I would start breaking it down until you get a stable IR and go from there myself.

Yes I agree. It’s at a GP surgery that’s been added and added to over the years. No documentation.

 

[TerryBNZ]

There aren’t any outside electrics on the circuit. Could the induced voltage be a clue.

Induced voltage can be a bit of a red herring when using DVM my guess is somethings moist.