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RCBO tripping mystery

Former Community Member
Former Community Member
Hello,

Can RCBOs trip if their integral neutral lead is too long?

Went to look at a tripping problem for a customer today, he had a lighting circuit and an alarm system connected to RCBOs that have started tripping.

As you will all know, an RCBO has terminals for the circuit live and neutral, as well as its own neutral that goes to the neutral bar. When I arrived, I found the RCBO neutrals for these two circuits disconnected and taped. I did a quick check by disconnecting the circuit neutrals and putting them directly into the neutral bar in the board, both circuits worked fine, as soon as I put the circuit neutrals back into the RCBOs and put the dedicated RCBO neutrals into the bar, which is how they should be configured, the circuits started tripping.

I noticed that the other circuits, sockets, immersion heater, etc. were also on RCBOs, but the dedicated neutrals for them had all been shortened. It was only the two with long neutral leads that were tripping. I asked the customer’s permission to shorten them to the same length as the ones on the other RCBOs, but he refused; I couldn’t argue with him as it was his property.

Thanks for any advice.

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    I once stripped out a consumer unit which had been installed with 25 mm boot lace ferrules on the seven strand 25 mm tails into the cage clamps of the main switch without the ferrules having been crimped.


    I pulled the ferrules off with my fingers and reinstalled the tails into the cage clamps of the new main switch without them. Having watched a few people on YouTube supposedly doing a "good job" by sticking ferrules on the ends of conductors that are being terminated into cage clamps it soon becomes obvious some of them don't know what they are for, often the same people who don't shrink heat shrink or cut it very short ?
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  • 0
    I once stripped out a consumer unit which had been installed with 25 mm boot lace ferrules on the seven strand 25 mm tails into the cage clamps of the main switch without the ferrules having been crimped.


    I pulled the ferrules off with my fingers and reinstalled the tails into the cage clamps of the new main switch without them. Having watched a few people on YouTube supposedly doing a "good job" by sticking ferrules on the ends of conductors that are being terminated into cage clamps it soon becomes obvious some of them don't know what they are for, often the same people who don't shrink heat shrink or cut it very short ?
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