In article , BigWallop
writes

Well, I'm sorry too, because I can't find anything, anywhere, that says a
standard RCD in a normal domestic installation will trip the supply unless
there is a fault from Phase to Earth.

You don't have to. Wire a plug with two wires, one to neutral and the
other to earth. Plug it into a socket and touch the two wires together.
Your RCD will trip; if it doesn't, it's faulty.

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..sigmonster on vacation