I went to a property to carry out an EICR.
Sockets and cooker were RCD protected all the other circuits were not.
I realise there is an order of doing the tests but I thought I would check the RCD test button. It didn't trip. I then did an RCD test and the RCD didn't trip.
Took the cover off the CU, started some dead tests on the ring. N-E 0MΩ.
Upon re-energising the ring the RCD kept tripping instantly as you would expect with a N-E short. However all the sockets had been working fine before I arrived!
After an hour of fault finding (as I couldn't leave him without sockets, even though it was just an EICR) I found a neutral touching a back box as the insulation was broken and there was no grommet. Fixed it and the IR results went to 50MΩ and the RCD then worked as it should. I.e the button tripped it and it tested as 11mS at 5x rated current.
My question is why was the RCD test button not working AND why did it not trip when tested? It only became a working RCD once the fault was found which kind of defeats the object!
Sockets and cooker were RCD protected all the other circuits were not.
I realise there is an order of doing the tests but I thought I would check the RCD test button. It didn't trip. I then did an RCD test and the RCD didn't trip.
Took the cover off the CU, started some dead tests on the ring. N-E 0MΩ.
Upon re-energising the ring the RCD kept tripping instantly as you would expect with a N-E short. However all the sockets had been working fine before I arrived!
After an hour of fault finding (as I couldn't leave him without sockets, even though it was just an EICR) I found a neutral touching a back box as the insulation was broken and there was no grommet. Fixed it and the IR results went to 50MΩ and the RCD then worked as it should. I.e the button tripped it and it tested as 11mS at 5x rated current.
My question is why was the RCD test button not working AND why did it not trip when tested? It only became a working RCD once the fault was found which kind of defeats the object!
