Andy Wade wrote:

Andrew Gabriel wrote:

Possibly some part of the earth leakage pathed has been burned out
now. Maybe the leakage is only marginal against the breaker's trip level.


Or perhaps something that got wet and has now dried out?

Sensitive "earth leakage" clamp meters like this
http://www.martindale-electric.co.uk/clamp.htm#cm67
are now being promoted as a good way of tracing faults causing RCDs to
trip.

Ohh nice... handy they numbered it the same as the Honeywell prog stat
to save having to remember another number. ;-)

I suppose the slightly cruder way I use to enhance the resolution of my
clamp meter could equally well be applied in these circumstances...

For doing accurate(ish) low current measurements with my "ordinary" true
RMS meter, I have a special short extension lead with about a meter of
outer insulation stripped from it in the middle, and each of the
conductors cable tied into ten turn coils. You can then clamp round one
of the coils and read ten times the actual current flow.

One could knock up a jig that allowed a flyling lead to be taken to the
CU, and the original leg of the power circuit taken to a junction box on
the test jig, and it provides a number of pre-wound coils to clamp round.

--
Cheers,

John.

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