On 10/11/2019 13:04, Jeff Layman wrote:
Last year we had a problem with our 5-year old Beko tripping the RCD
when it was turned on (NB it had been modified during a recall shortly
after we bought it). It only did it on that one day and has been fine
since.

A month ago it ran through its drying cycle with no problem, and beeped
that it had finished. We removed the dry washing, and took it away. When
we returned a couple of minutes later, we found the RCD had tripped.
This has occurred twice again - the dryer is fine working, but trips the
RCD as it cools down. Once cool, it seems ok and can be used again.

I have seen this sort of fault the other way around with failing kettles
where there is an initial RCD fail when used from cold but the thing
will then work for a good while after you have reset the breaker.

Eventually it fails completely and never recovers.

I'll have a look inside to see if there's anything obvious, but has
anyone heard of a fault which behaves this way?

My guess would be condensation getting somewhere that it can provide an
earth leakage path.

It may be time for a new drier, but I'm intrigued as to what this one is
doing.

Can you measure resistance (when unplugged) from live to earth and
detect any difference in the failed state?

--
Regards,
Martin Brown