I have a 1990's built house and about a year ago updated the consumer unit from fuse wire to plug-in ECB's. Everything has been fine up till a few days ago when the downstairs lighting circuit tripped.
I reset it and it tripped again about 10 minutes later.
After re-setting I have gone through the house switching on each downstairs light in turn but all lights work OK and none cause the ECB to trip.
I have removed all dimmer switches and replaced them with standard on/off switches but the same thing still happens.
I've swopped relays to see if that made any difference but it didn't.
I can't identify any action which causes the ECB to trip and it often trips when no downstairs light is on and as far as I can see the circuiit is inactive.
Sometimes when I reset there is a flash in the relay and it won't re-set, othertimes it just clicks and all is well - for a while...
The only thing I have been doing is replacing tunsten bulbs with energy saving versions but the upstairs circuit works fine with the new bulbs.
I am at a loss what to do next - any suggestions gratefully received!