On 06/08/2013 09:58, Lobster wrote:
Currently being driven nuts by the above... I have a split load CU.
When the RCD trips, it's only that which goes; ie none of the MCBs
trips at the same time which means there's not much for me to go on.

Question 1: if, for diagnostic purposes, I switch off each circuit in
turn by manually flipping its MCB, does that actually isolate the
circuits for the purpose of elimination? Or would I need to open the
CU and physically disconnect all the cables from each circuit in
turn, completely?

Question 2: what does the fact that no MCBs are tripping; and the
trips occur at apparently random intervals (4-5 times in the last
day, with interval of up to ~10 hours so far, and including an
overnight trip; and no problem with reinstating the RCD immediately)
tell me about the nature of the fault, if anything?

Thanks for any pointers!

Thanks for all the replies. It hasn't 'popped' since 5 am today (it's
now 9:30 pm so hopefully whatever it was has gone away... I'm suspecting
it might have been cat pee actually; no evidence but we certainly have a
problem here that way

--
David