So...I installed a new[Crabtree unit off Ebay] split load CU in my parents Park Home at the beginning of the year. Non protected side = 2 x 6amp light circuits, 1 x 32a circuit for boiler and fridge freezer, protected side [30ma]: 2 x 32a socket circuits and 1 x 32a oven circuit. This is a small residential Park Home.
Earth is TN-C-S
Problem: Nuisance RCD random tripping. Remove all appliances, check sockets, check wiring etc....nothing obviously visible. RCD still trips, sometimes from pc, sometimes tv, sometimes kettle...but nothing obvious...etc
Temporary solution: put offending circuits over to the non-protected side, but leave Oven circuit on RCD side. Oven has never tripped RCD since.
Having left it like this for too long: Father does some tiling in the kitchen and gets a considerable shock from the earth on one of the sockets. This particular socket is on the ring, but has a spur feeding a washing machine. Jumping to uneducated solutions we guess it's the washing machine [which is new] that has been causing all the problem. Service engineer comes and passes the washing machine as being fine, but says he can detect a voltage in the earth with his meter [I wasn't there at the time].
I have had all the circuits out from the CU, and done simple continuity checks, I've checked sockets, wiring where I can, earth connections from the meter back to the CU, but can find nothing. I'm clean out of ideas.
I suspected the RCD might be faulty originally, but the fact that it hasn't tripped at all with only the oven, and the fact that my father got a kick from the earth points to a different kind of fault.
Like I said, I think I'm almost at the point of handing it over to higher powers, but is there anything I might want to look at?
Appreciate any input.