O
So, to sum up, I still say an RCD will not trip open unless the fault
current it detects is between a phase potential and earth mass.

Boy, can I go on a bit when I get started. :-) LOL !!!

I must have a faulty one on my bench at work then, always trips on neutral
to eath fault.

Dave

--
For what we are about to balls up may common sense prevent us doing it
again
in the future!!