Disaster has struck. For no apparent reason the RCD on my MK Senrty CU has tripped. I cannot get it to reset which suggests to me that either a) the DCD is knackered or b) there is a fault on the fixed wiring. I've tripped all the MCB's to try to isolate the circuit with the fault but this has not helped as even with all the MCB's to off the RCD will ot reset. Nobody in the house was using/doing anything out of the ordinary when it tripped. House was rewired 9 years ago.Any ideas ?
Neil