On 20 Sep 2003 20:08:52 GMT, wrote:

In uk.d-i-y, tony sayer wrote:

The RCD has nothing to do with the earth as such. All it does is look at
the current into the protected circuits, on the live and checks that the
same comes back out on the neutral. Any imbalance i.e. leakage to earth
then it will trip the level needs to be about 15 ma or so..

This is an accurate description of a modern RCCD. However, the earlier
type was voltage-operated - it would look to see when the house earth
potential had risen to more than 50V above that from the earth rod (!).

Must admit, this was the first thing that crossed my mind when I read
this thread. First thing, get someone who knows the difference to see if
you have a voltage operated trip.