Minimum values of insulation resistance

mapj1:

I'm not saying an NE short is a good thing - far from it, but If all it does is lower R2 or trip an RCD prematurely above some modest level of load, then is only being a pain to the user, not the same 'immediate ' danger comparable to exposed live parts.

I don't think RCD tripping prematurely is the only outcome. RCD not tripping at all is another possibility (but perhaps not too common thankfully).

Only a really badly designed system becomes dangerous in a power cut and I'd hope they have back up power or some pre-arranged back-up supply.

And as noted above, when we started putting RCDs in, quite a lot of dormant N-E faults were found and had to be fixed, suggesting they had been around a while.

mapj1:

I'm not saying an NE short is a good thing - far from it, but If all it does is lower R2 or trip an RCD prematurely above some modest level of load, then is only being a pain to the user, not the same 'immediate ' danger comparable to exposed live parts.

I don't think RCD tripping prematurely is the only outcome. RCD not tripping at all is another possibility (but perhaps not too common thankfully).

Only a really badly designed system becomes dangerous in a power cut and I'd hope they have back up power or some pre-arranged back-up supply.

And as noted above, when we started putting RCDs in, quite a lot of dormant N-E faults were found and had to be fixed, suggesting they had been around a while.