If that was really a problem the 250' of extension cord I had strung out yesterday should have tripped the TWO GFCIs (in series) that were feeding it. We were running a table saw, several drills, an impact wrench and a skill saw with no problem at all. This is very common in construction sites all over the country where they run very long cords from T poles or the garage across the street. Why isn't this "capacitance" and the "motor myth" shutting down construction sites?
I put this in the same class as those who say refrigerators and washing machines are supposed to trip GFCIs. GFCIs trip on ground faults.
I am planning on doiong some pressure cleaning next week and we will be using my 50 foot 30a 240v SO extension cord (5HP motor). I will put a clamp on it and see what the ground current is at the source. If 100' of SO cord is supposed to trip a GFCI I should see 2-3ma of ground current from 50 feet (plus the 35 foot SJOW cord on the cleaner).
BTW your example of a "good" meter only means that it has many megohms of impedance so microamps will excite it.
OK folks
Want to get your bets down?
50' of 6ga SO cord
35' of 10ga SJOW cord
35' of 10ga Romex
5HP motor load on the end
Will I measure on the green wire at the panel?
(A) much less than a milliamp
(B) about 1ma
(C) 2-3ma
(D) 4-5ma
(E) Greater than 5
