RCD FAULT

[HLR Electrical]

Hello, I’ve just been to a job and their RCD has it’s moments and trips throughout the day but doesn’t on other days. When I was there I tested all appliances and put everything on but couldn’t get it to trip. Very weird.
I noticed the test button on the RCD wasn’t working AND was getting slight continuity between incoming live and neutral through the RCD in my two prong megger continuity testers. I’ve changed the RCD for a new ones as I thought it would be faulty. New one is okay and all circuits not tripping it.
Anyone come across this before or any advice if it isn’t a faulty RCD?

I’ve told the customer to contact me if it continues tripping.

 

[MJPD29]

Did you ramp test RCD of carry out any insulation resistance testing?

 

[ipf]

Did you ramp test RCD of carry out any insulation resistance testing?

A faulty RCD with a dodgy test switch indicates the problem, sort of....especially if a replacement works without any issues. Always fully test a replacement.

 

[ipf]

Hello, I’ve just been to a job and their RCD has it’s moments and trips throughout the day but doesn’t on other days. When I was there I tested all appliances and put everything on but couldn’t get it to trip. Very weird.
Anyone come across this before or any advice if it isn’t a faulty RCD?

It can be quite common and you could almost say 'it could be anything'. It's a case of testing and process of elimination. An earth leakage test instrument could prove to be handy.

 

[HLR Electrical]

Did you ramp test RCD of carry out any insulation resistance testing?

I didn’t have my proper testers on me as I went in the car but went with an earth leakage clamp metre and all was good. If problems persist I’ll fully test the board when I’m back.

 

[Lucien Nunes]

slight continuity between incoming live and neutral through the RCD

Can you put that in ohms? It's odd, nearly impossible without the RCD blowing up, and deserves explanation. Was the RCD completely disconnected from the outside world when you made this test?

 

[HLR Electrical]

Can you put that in ohms? It's odd, nearly impossible without the RCD blowing up, and deserves explanation. Was the RCD completely disconnected from the outside world when you made this test?

Everything disconnected. Continuity Testers were bleeping and flashing super fast as if a connection was being made then broken really quickly. I’m thinking it’s just the RCD being faulty and creating some kind of weak connection inside. Either that or my testers are playing up