In article ,
Harry Bloomfield wrote:
wrote :
The suggestion re carbon in the motor could well be worth looking at.
I reaplced the brushes in the motor with new ones about 3 months ago,
so it could be 'dusty' in there. That said, it trips even when the
control knob is set to somethign that doesn't immediately run the
motor.

Be aware that a neutral to earth leakage can also cause a trip, not
just a live to earth leakage - many people forget this. So even an item
turned off/ live disconnected can still cause an RCD to trip if it is
plugged in, yet turned off.

but very rarely if it's unplugged

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle