The RCD in my split-load CU trips out occasionally, something like every other month. No obvious cause, and it generally happens at night. I want to identify the cause, or at least narrow it down, but the random nature plus the low frequency is making this quite difficult.
I've got a multimeter, and have made up some "leakage plugs" with resistors from live to earth, but I think I need some more specialist test equipment, specifically an insulation tester to check each of the RCD-protected circuits and an RCD tester to check the RCD device (and test the new one if it needs replacing).
This equipment is quite expensive, and it's not something I'm likely to use often. Does anyone know if it's possible to hire this sort of equipment for a reasonable cost? Any pointers to good hire shops that might carry it?
Alternatively, are there any sources of cheap test equipment for this sort of thing that would be suitable for light DIY use, or are these things always several hundred pounds?
I've got a split-load CU with an 80A / 30mA RCD protecting all the power circuits. The lights and immersion heater are not RCD protected.