RCD trips when screw touches lug

[mnrifai]

DIY question.

I have been changing old metal socket faceplates to the normal plastic ones. All are working fine except the faceplate of a fused switch. Everything works fine when it isn’t screwed. It is a fused spur for a light in the conservatory.

The light works fine when the screws are off even when pushed back but as soon as a screw touches the lug the RCD trips.

 

[westward10]

You need to check it is correctly terminated and that you haven't damaged the insulation of the conductors.

 

[littlespark]

Compression fault?

Cables are so squashed together that insulation is thinned or rubbed away. Hanging out on cables, ok, but pushed back with force will trip.

Or as above, the screws are nicking into insulation and touching a conductor.

Will happen between neutral and earth, not just live and earth.