On 19/02/2019 14:03, Roger Hayter wrote:
I disagree. Any measurable leakage (at least with ordinary instruments
outside of a lab) is evidence of impending failure.

No it is not.

The 'insulation' insde a heating element in particular is not an
absolute insulator.

It is in general Magnesium oxide. Because that has excellent thermnal
conductivity.

The great danger inimmersin heaters is water ingress. But if that gets
in te ting will show very low resistance




Anyway, he's got a
Megger so can test it on the bench and hopefully let us know the result.
He could always heat it with a plumbing blow lamp if it is still
borderline.

RCD are designed to cope with some leakage. All elements leak. The
question is how much.

I dont regard half a megohm as interesting at all.



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