Ok, I've heard it all...was working on a job where the cover was left off a 240V sub-box. So the busses were exposed - a potentially lethal setup.
Me and the GC took a look at the main panel in the basement...a breaker said to serve that sub-panel (with appropriate red & black wires) was pulled from the bus there, and also "off".
But, my GB proximity indicator ("non contact voltage tester") went off and showed the sub box as "live". The electrician stated that sometimes a "static charge" can build up in the sub box and give a false positive when using a proximity detector.
I want to call bull on this. Capacitive re-charge? To the 50V necessary to set the thing off?? And - I believe these proximity detectors require AC CURRENT FLOW to go off???
Either that or we've just encountered a really cool but little discussed phenomenon. I don't want to get the electrician into hot water, but I also don't like to be made to look the fool, so I haven't said anything.
Thoughts?
Me and the GC took a look at the main panel in the basement...a breaker said to serve that sub-panel (with appropriate red & black wires) was pulled from the bus there, and also "off".
But, my GB proximity indicator ("non contact voltage tester") went off and showed the sub box as "live". The electrician stated that sometimes a "static charge" can build up in the sub box and give a false positive when using a proximity detector.
I want to call bull on this. Capacitive re-charge? To the 50V necessary to set the thing off?? And - I believe these proximity detectors require AC CURRENT FLOW to go off???
Either that or we've just encountered a really cool but little discussed phenomenon. I don't want to get the electrician into hot water, but I also don't like to be made to look the fool, so I haven't said anything.
Thoughts?