So got called out today... cooker circuit tripping the RCD. Turns out, it's cooker, sockets and extractor hood on a 16A breaker, with washing machine on one, gas hob, electric oven.
Get's it down to a L-E short on the cable from the CU to the SFCU that has the hob and oven connected to it, yes... both of them on one. Turns out there are two sets of cables in the conduit, great I think, pull some slack through and use the other L... except that has a L-E short as well. Ok, use the neutral and sleeve it... Couldn't get any movement on it and it's snipped off close to the wall at the far end... nightmare.
But check out this quality work...
Lovely bit of arson there from a gas fitter.
View attachment 47247
View attachment 47248
View attachment 47249
The conclusion I've drawn is (because apparently the RCD tripping has been going on for a while getting more and more frequent) is that some plum has hammered/damaged the conduit and consequently the cables and it's finally given up. Would have been grand if I could have pulled the slack through, but as it is got to run a new cable and make it safe. What a bloody lash up.