KevCompton wrote:

Thanks for your reply, very useful. Earlier, I did a bit more checing
and it looks like different circuits are connected to each other. I
will do as you suggest and remove all wires on the problem circuits and
see what is connected to what. All the problem circuits are for the
sockets throughout the house.

You mentioned that the wiring may have loads that run from live on one
circuit to N on another. I think that may be my problem as continuity
between two L contacts on different circuits existed even though I had
disconnected them from the CU, leaving only the N and Earth still
connected. Why would this be done? Is it a normal thing to do in
certain conditions?

Thanks.

Its quite common, if not best practice. If it were me I'd be asking
which of the problem circuits actually need to be on RCD. Either that
or you've got a bunch of tracing and rewiring to do.


NT