6 Sep
2014
6 Sep
'14
2:08 p.m.
On Sep 6, 2014, at 3:43 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
I don?t know the limits in the US either, but I agree 100% with your sentiment. Wire
insulation and other insulation in transformers, when in good condition, should have
impedance in the hundreds of megaohms at least, if not higher. One megaohm indicates it?s
suffering serious decay. Either that, or it?s 80 years old and built using materials that
were both very low tech and very low quality (i.e., ?cheap junk?). Note that some of the
very best insulators have been known and in use for over a century, so age alone does not
excuse high leakage.
paul
At any rate, I
don't think you need to worry about 90 microamps leakage.
Most US GFCIs don't trip until the leakage current is somewhere around
6 ma--or about 60 times what you're seeing.
I am not sure what the legally allowable leakage current (to pass a PAT
test) is in the UK, but personally, if the leakage resistance is gettign
close ot 1M Ohm I want ot know the reason why.