Ever since the house was built it's had te odd nuisance trip.
What happens is that every spo ofetnm some surge will take out te now
100mA whole house RCD even though its virtually empty of any kit these days.I can RELIABLY make it trip by connecting a high startup current device
- like an angle grinder - to the ring that feeds my workshop and hobby room.
The same device connected to other rings is fine.
In other cases it takes a real surge - bulb blowing short - and it trips out.
I am thinking earth neutral short on that ring.
What do you think?