There are some faults that trip a GFI but don't show up at very low voltage, i.e. with a multimeter. This is where a megger gets really helpful, because its test voltage is much higher.
got it, of course. i usually think about voltage . . . eer amperage I mean when I think about it . . . as breaking down continuity. so you can test and get continuity on a circuity but apply load and the continuity breaks down at a corroded or loose connection somewhere.
and of course with very high voltages I think of faults -- , i.e continuity to ground as becoming more likely, but, of course, 110V is well more than the testing voltage on standard tester.
unfortunately the meggers are well more than I can spend to confirm that there is a fault at 110V on this $5 extension cord, so I guess I will have to accept that trying this on several GFCIs and getting the same result is definitive. unless and until I find a friend who has one, my mind is whirring on that. You see, I know this linesman . . .
thanks for the note
brian
