BS7671 Insulation resistance testing

.2 stages................250v first fix.................500v second fix

other way around surely? 250V once the equipment is connected..

   - Andy.

grahamro said:

Nice idea and we should have some form of testing for first fix but inevitably with the builder/ plasterer standing right behind you with trowel in hand how often does/will this happen?

speaking only personally perhaps, and from many years ago,  I think it happens on the jobs shortly after the one where you found you had to chase across a newly plastered wall to pull a cable to correct something that may well have shown up in earlier testing.  A plasterer tapping his trowel behind you is mildly less stressful than arguing who pays for the same plasterer recalled a few days later when the fault has been discovered. It is also why I like oval conduit for things prone to damage like switch drops - but I do not do much with house wiring these days.

Some folk compromise and do funny things like use the megger on cable reels before use, though unless you are very ham fisted with how you store and transport cables, I think most damage occurs after that.

Mike.

That is what I meant honest!!  Edited to suit.....

but inevitably with the builder/ plasterer standing right behind you with trowel in hand how often does/will this happen?

I guess it doesn't have to be done before plastering - just before you start connecting current-using equipment would do (and having a few passive accessories (e.g. switches) in place probably makes it easier in that you can likely test most of a circuit in one go rather than each cable individually), plus you're then testing at 500V for any damage the plasterer has done with his razor sharp trowel.

   - Andy.