I'm not an "electrical" guy, but I've been pondering this probe idea since yesterday and it makes me nervous and I'm not sure if it's for a valid reason. 0311, perhaps you can tell me if I'm worrying about nothing here. And I'm thinking about checking broken wires, not intact circuits here, because building collapse or some other calamity seems to be the scenario that you envision using it. Maybe I'm just confused about where the ground in an AC system needs to be.

Couldn't a wire be "dead" according to this probe, but then you actually get shocked if you touch it because you just completed the circuit to ground? I guess I'm thinking that this probe only works when current is actually flowing at the time you test it. No current = no EM field. It seems to me that it won't tell you if the line is actually not hooked up to a power supply or not. Does this question make sense?