what you need to do JD is make a flylead from some cable, do your 12v bulb setup, turn off CU, remove earth cable for this particular light circuit, and then go to your furthest light fitting, link one end of the earth cable to the lighting earth at the CU
then take the other end to the furthest point.
this is a good, although wont tell you of high resistances ect, way of checking.
but i would advice you to go for an atleast £9.99 multimeter
my test gear has cost me well over 2 grand, obviously you wouldent need most of it, but my £60 quid multimeter holds its own
i still think its induction.
it can appear at the lighting point and not at the CU, think of it like an earth rod, your one, the supply is one.
your closer as a path.....
electricity always takes the shortest route, which is great, unless its across your chest....
its good your checking JD.
i agree there could be a break in the earth cable, but i think its unlikly because ive come across this before, which is why the neon in my box is used as the party piece only
ss
oh btw stoday, just thaught id let everyone know here
STODAYS APPLICATION TO TRADE WAS REFUSED.
on the grounds of being totaly unqualified, and showing no evedence of being so.
whoops....did i say that