Insulation Resistance

[walec]

Evening all,

Been to a job today to add some sockets to a ring, Did a quick IR test and got >299 L-N >299 L-E & 35 N-E, checked out continuity, Zs, all fine, the L-E has got me a bit stumped, any ideas? cheers.

 

[monkeyelectric]

Evening all,

Been to a job today to add some sockets to a ring, Did a quick IR test and got >299 L-N >299 L-E & 35 N-E, checked out continuity, Zs, all fine, the L-E has got me a bit stumped, any ideas? cheers.

Cable been damaged somewhere, either something has partially breached the sheath or its squashed somewhere,or in a socket or switch box, can you break the circuit down into legs to find out which leg is at fault?

 

[Eggster71]

Also you did isolate the neutral and earth at the board didn't you?
Don't forget resistances in parallel like that will be reduced.
Other than that ^^^^what he said, take a socket off and test either way, keep sub-dividing. Good luck.

 

[Mr Mark Sparks]

why does this need investigating 35 meg is well in

 

[monkeyelectric]

why does this need investigating 35 meg is well in

You're right and I personally wouldn't investigate further but he asked what the cause would be

 

[walec]

Thanks guys, I am not planning to investigate further it is well in spec, it was just the difference that had me thinking, somtimes thinking too much!

 

[glasgowspark]

why does this need investigating 35 meg is well in

While this is true, I would always mark down on the Minor Works Cert as a footnote to have a Periodic carried out within a year. That way youve sort of covered your behind.

It is important to have the Periodic carried from time to time because that 35 meg is probably going to get less and less until the lights go out. By keeping an eye on the numbers dropping over a period of time you can then decide when enough is enough and further investigation should happen.