On 22/06/2013 03:06, John Rumm wrote:

Nice plan...

Might be worth adding a step of doing an additional probing before
energising the circuit, just to establish that you are not going to be
lead up the garden path (so to speak) by stray ground currents from
other sources not connected with the actual circuit in question.

Good idea - and in retrospect my suggestion to use mains earth as the
voltmeter's reference point wasn't too clever, especially it's PME. A
'clean' reference spike somewhere in the garden, but known to be well
away from the lighting cables, should be a much better bet.

--
Andy