"Ian White" wrote in message
...
KevCompton wrote:
Thanks for all the prompt replies.
I'm 95% sure that I had all the neutrals on the RCD protected neutral
bus bar as I had to swap them over to the non-RCD protected neutral bus
bar to get things working temporarily on the problem circuits. Are
there any other possible reasons?


The missing 5% of "sure".



I had to remove a power factor capacitor from a fluorescent lamp once. It
was isolated and most definitely only connected to live and neutral yet
virtually every time I switched it on it would take out the RCD.

I also had a computer which I learnt to leave permanently switched on and
only turn it on or off at the wall.

Equipment with mains filtering can be an issue. I've isolated capacitors
before now so there's no connection to earth.