Why was the RCD test button not working?

HappyHippyDad · Mar 9, 2018

Evening all...

I have just got back from a CU change. All was going very well and I was finishing early which was lovely for a friday evening, and then.......

The RCD on the opposite side to the lights trips when the lights are switched on... arghh. I eventually found the problem, I had screwed through the shower cable when attaching the CU to the piece of wood I was using to hang it on.

Whilst the screw was still through the shower cable (touching N-E) why did this stop the test button from working on the RCD? There was 240V going through the RCD and by using something on the other side of the dual RCD board it would trip, but it would not trip with the test button?

Cheers.

westward10 · Mar 10, 2018

No it was a clever idea but as you say the line connection is concealed and a pig to reconnect on an EICR with two 4.0mm conductors.

SparkyChick · Mar 10, 2018

westward10 said:
No it was a clever idea but as you say the line connection is concealed and a pig to reconnect on an EICR with two 4.0mm conductors.

Never done it, but I can feel your pain. I was contending with three 2.5mm and that was bad enough.

westward10 · Mar 10, 2018

If I had a pound for every time I have cursed these things are a pain in the bl**dy ar*se I would be a rich man.

plugsandsparks · Mar 11, 2018

Ha, reminds me of panel wiring where the panel builder puts all the terminal blocks low down at the bottom of the panel. He can see to put his wires in the top side but FFS its near on impossible to "know" where the hole is for the outgoing, end up using the force and trial and error which leads to a bad back and me being grumpy for the rest of the day.