Kev wrote:
Dave Plowman (News) wrote:
How did you 'narrow' it down? Simply switching off an MCB doesn't disable
that circuit as far as an RCD is concerned - a neutral to earth fault will
still trip it. The only way to truly disable the circuit is to disconnect
line and neutral.
By far and away the likely cause is a faulty mineral insulated heating
element. To be found in immersions, washing machines etc and ovens.
--
*Stable Relationships Are For Horses.
Dave Plowman London SW
To e-mail, change noise into sound.
I flicked off each MCB then switched them on in turn, as soon as the
down stairs ring mcb is switched the RCCD trips out. I must admit that
I was surprised that it was the down stairs ring as it is usually a
circuit for the garden with pond pumps that trips. Failing that it has
always been the kettle or the wife's rice cooker so having disconnected
everything I am puzzled why it still trips.
Kevin
This effect can be deceptive.
I had a similr problem and thought that I had narrowed it down as well.
As it turned out, the only only reason that the RCCD tripped was
because of the MCB load suddenly appeared on the RCCD [and the load
only needs to be marginally out of balance (before it settles) to trip
out the RCCD!]
Thus giving a false impression.
There is no easy way without a megger (which is the way I did it in the
end).
Cheers
Peter