Hi all you wise, experienced sparkies out there..... I'm only just qualified and my first job is to diagnose nuisance (usually happens in thunderstorms) tripping of the supply "Earth Leakage trip device" (100mA). I initially assumed this was an RCD but apparently I have since learned it could be a voltage device, not current. It is very old and this is an old problem that my friend would like sorted if poss. it is fitted between the main fuse and the meter, i.e. the whole supply.
It is a TT system and has a Ze of around 125 ohms, so this seems ok? Western Power are coming to fit an isolator upstream of this - i had hoped they could just swap the device with a isolator switch but no can do, its up to me after they fit the isolater. There is a 30mA rcd in the CU but this one doesnt usually trip. I have been advised by my tutors that the rcd protection must be 100mA on a TT system, so after they fit the isol;ator I was planning to replace device with a 100A / 100mA rcd in the same place (Wylex price is reasonable from TLC). Does this sound ok? Cheers, Mike....
It is a TT system and has a Ze of around 125 ohms, so this seems ok? Western Power are coming to fit an isolator upstream of this - i had hoped they could just swap the device with a isolator switch but no can do, its up to me after they fit the isolater. There is a 30mA rcd in the CU but this one doesnt usually trip. I have been advised by my tutors that the rcd protection must be 100mA on a TT system, so after they fit the isol;ator I was planning to replace device with a 100A / 100mA rcd in the same place (Wylex price is reasonable from TLC). Does this sound ok? Cheers, Mike....