Sorry about the naive and simplistic subject, which (once again) reflects my knowledge of things electrical.
Our consumer unit tripped off this morning - the main trip, that is, not one of the circuit trips.
By elimination I tracked first the circuit and then the thing that tripped it, which turns out to be the pond pump. Or rather, more likely: the chain of cables and connections that connects the socket in the house with the pond pump. I suspect that water has got into one of the connection points: haven't had time to check it yet.
My question is: why does this trip the main switch on the CU, and not just the circuit breaker for that ring main?
Thanks for any replies Cheers John