Ali
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- May 10, 2009
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I was changing a CU today and didn't do an IR test before I started (that's a lesson learned). All went well until I started turning the new duel RCD board on.
I turned on the main switch and then the first RCD. I pressed the RCD test button like all good leccies should and nothing happened, the RCD didn't trip. All MCBs are off at this point.
I narrowed the problem down to one of the lighting circuits on that RCD. If both the neutral and the CPC were connected in the board, the RCD test button didn't work and the RCD didn't trip at
or
.
I disconnected the circuit and found that there was continuity between the neutral and CPC.
Looked in lots of the light fittings until I found the problem, rectified it and all was good with the world again.
My question is, why would a properly working RCD not trip if there is a neural to earth fault, I would have thought it would trip all the time and not reset.
It seems that I don't understand RCDs. Anyone able to enlighten me?
Thanks
I turned on the main switch and then the first RCD. I pressed the RCD test button like all good leccies should and nothing happened, the RCD didn't trip. All MCBs are off at this point.
I narrowed the problem down to one of the lighting circuits on that RCD. If both the neutral and the CPC were connected in the board, the RCD test button didn't work and the RCD didn't trip at
I disconnected the circuit and found that there was continuity between the neutral and CPC.
Looked in lots of the light fittings until I found the problem, rectified it and all was good with the world again.
My question is, why would a properly working RCD not trip if there is a neural to earth fault, I would have thought it would trip all the time and not reset.
It seems that I don't understand RCDs. Anyone able to enlighten me?
Thanks