Jerry Lozier Posted March 27, 2009 Report Share Posted March 27, 2009 I use a noncontact AC voltage detector to test for live wires, ( knob and tube etc) however seems to go nuts in high static area, sometimes within a foot or two.... so can be unreliable at times any voltage tester out there that is not as suseptible to static or other suggestions?? thanks Jerry Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted March 27, 2009 Report Share Posted March 27, 2009 I use a noncontact AC voltage detector to test for live wires, ( knob and tube etc) however seems to go nuts in high static area, sometimes within a foot or two.... so can be unreliable at times any voltage tester out there that is not as suseptible to static or other suggestions?? thanks Jerry All non-contact voltage detectors are highly unreliable. They'll give both false positives and false negatives. Never rely on one in a life-threatening situation. They're not really voltage detectors anyway, there're electric field detectors and, as you've discovered, they'll react to any electric field. Worse, if the wire you're testing is shielded, the tester won't tell you that the wire is hot. If you want something reliable, use a multimeter, a wiggy, or a simple neon light tester. Only use the non-contact sticks when the results really don't matter. - Jim Katen, Oregon Quote Link to comment Share on other sites More sharing options...
mthomas1 Posted March 28, 2009 Report Share Posted March 28, 2009 Has anyone here ever seen a false negative on K&T if you are able to get the tip in actual contact with the insulator/conductor - that's all I ever use them for. Quote Link to comment Share on other sites More sharing options...
Richard Moore Posted March 28, 2009 Report Share Posted March 28, 2009 any voltage tester out there that is not as suseptible to static or other suggestions?? I had one once, a GreenLee I believe, that was overly sensitive to the point that I couldn't even use it to determine polarity in a 2-prong, ungrounded outlet. Anywhere in the vicinity of the receptacle and it would light up. It may have to do with the voltage sensing range(...?). Anyway, I've been using Flukes for a while that don't have that issue. I do think they have their uses as long as you understand their limitations. Besides KT wiring, I also find them very handy for quick checks of AFCI & GFCI protected receptacles (basically to make sure they are off) and checking that ceiling fans are grounded. A fridge plugged into a hidden ungrounded receptacle (via one of those damn "adaptors") will also light up the tester touched to a metal part, like the hinge, if the compressor is running. Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted March 28, 2009 Report Share Posted March 28, 2009 Has anyone here ever seen a false negative on K&T if you are able to get the tip in actual contact with the insulator/conductor - that's all I ever use them for. Well, sort of. It depends on what's on the circuit and how much current it's drawing. If there's no load, you'll get a nice strong reading with the non-contact stick. If there's a heavy load, the reading will be much weaker and might even be intermittent with some brands of tester. The same thing happens with radiant heating cables. - Jim Katen, Oregon Quote Link to comment Share on other sites More sharing options...
David C. Argabright Posted March 28, 2009 Report Share Posted March 28, 2009 I use a Greenlee with a sensitivity dial. I always carry it but don't totaly rely on it. I've only had one through the years that I somewhat trusted. I don't remember the name and I left it lying somewhere years ago. Quote Link to comment Share on other sites More sharing options...
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