EDIT:
faulty fire alarm sensor spurred within ceiling was causing the RCD to trip.
not mentioned in paperwork.
all other sensors are on a separate ring, so this one is a mystery.
electronic device which caused L-E fault only when powered up so this would have probably came up on a megger (if i was to call an electrician and i was close to doing so), but did not show the fault with a 9V multimeter.
essentially, i dismantled the ring and tested all tails and all sockets, to find a perfectly healthy ring with no faults and still tripping one RCD...
i hope that my experience will help someone.
:EDIT
TT system with earthing electrode.
Split load board with two 30mA RCDs.
One RCD trips.
Identified the tripping circuit to 'downstairs sockets'.
All other circuits protected by this RCD function properly (cooker, lights, fire alarm, central heating, kitchen sockets).
All other circuits protected by another RCD also function properly and the other RCD does not trip.
MCB 'downstairs sockets' does not trip. Only the RCD.
When this MCB 'downstairs sockets' if OFF, RCD stays ON.
When this MCB 'downstairs sockets' is ON, RCD trips instantly (<0.5s).
The 'downstairs sockets' circuit contains 7 double sockets.
All devices disconnected - all plugs removed from sockets. All sockets in OFF position.
Still trips as above.
Opened one socket and measured L-N open, L-E open, N-E ~40 Ohm.
There was no work done around the house, no leaks.
What can I test? What would it be?
faulty fire alarm sensor spurred within ceiling was causing the RCD to trip.
not mentioned in paperwork.
all other sensors are on a separate ring, so this one is a mystery.
electronic device which caused L-E fault only when powered up so this would have probably came up on a megger (if i was to call an electrician and i was close to doing so), but did not show the fault with a 9V multimeter.
essentially, i dismantled the ring and tested all tails and all sockets, to find a perfectly healthy ring with no faults and still tripping one RCD...
i hope that my experience will help someone.
:EDIT
TT system with earthing electrode.
Split load board with two 30mA RCDs.
One RCD trips.
Identified the tripping circuit to 'downstairs sockets'.
All other circuits protected by this RCD function properly (cooker, lights, fire alarm, central heating, kitchen sockets).
All other circuits protected by another RCD also function properly and the other RCD does not trip.
MCB 'downstairs sockets' does not trip. Only the RCD.
When this MCB 'downstairs sockets' if OFF, RCD stays ON.
When this MCB 'downstairs sockets' is ON, RCD trips instantly (<0.5s).
The 'downstairs sockets' circuit contains 7 double sockets.
All devices disconnected - all plugs removed from sockets. All sockets in OFF position.
Still trips as above.
Opened one socket and measured L-N open, L-E open, N-E ~40 Ohm.
There was no work done around the house, no leaks.
What can I test? What would it be?
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