I recently rewired upstairs lighting circuit (in Scotland so no Part P legislation). 1 circuit for upstairs lights, 1 for bathroom/ shower lights (RCD protected).
At first the RCD tripped when I connected the new upstairs circuit. In attempt to find fault I connected a new cable straight from CU to first junction box in circuit - RCD still tripped.
However, when I connected first junction box to circuit intended for shower lights, the RCD didn't trip.
Both scenarios involve cable going directly from CU to first junction box.
I now intend to run a new circuit for shower lights but any thoughts on why RCD might have tripped?
At first the RCD tripped when I connected the new upstairs circuit. In attempt to find fault I connected a new cable straight from CU to first junction box in circuit - RCD still tripped.
However, when I connected first junction box to circuit intended for shower lights, the RCD didn't trip.
Both scenarios involve cable going directly from CU to first junction box.
I now intend to run a new circuit for shower lights but any thoughts on why RCD might have tripped?