RCD trip

[DirtyDog368]

Hello All,

New the game and this forum so please bear with me.

I have just changed a customers old consumer units for one compliant with 17th edition. The circuits were all muddled up and it took a while to figure out all 18 wires and what they did. However the last "circuit" which due to the process of elimination i think is part of the downstairs lights trips the RCD as soon as the phase or neutral touches their connection in the fuse box.

From what i understand RCD measure current on the phase and compare it to that of the neutral and if they dont match up, trips.

The consumer unit is live when this happens.

If any one has any leads and suggestions they would be gratefully accepted.

Many thanks for your time.

DD368

 

[malcolmsanford]

You seem to have a "borrowed" neutral type in this on the forum search engine and you'll see lot's of threads about it and how to over come it.

It is normally on the 2 way light from the downstairs light to the top landing light, many older houses where a 2 way lighting circuit had a neutral was "borrowed" neutral.

Best way to check is double up the 2 lighting circuits into one MCB for now, making sure that both neutrals for the circuits are in the same neutral bar.