Today I saw something I have not seeen before, When testing some receptacles in a house, I had my plug tester light all 3 lights. Thinking that maybe something was wrong with the tester I went out to my truck and grabed the two other plug testers I have and restested. All three plug testers had all three lights light up. The recep was wired correctly. Voltage test with a meter was normal (116.5 volts). So far I have not found any thing wrong. Any Ideas ?????
My guess would be a high resistance ground with some leakage current. This might allow it to be biased roughly half way between neutral and line and light up neons all three ways. Come to think of it, they could probably self bias half way. It is really strange to me that you post this now because I had a fellow Testing Engr. borrow mine today. I told him I never use it as I pulled it out of my desk drawer. He had to test many outlets fast though and it is sometimes hard to get the Fluke probes in contact. I did look at the legend on mine though and it didn't show all three on. Joe
Re: Strange reading on plug tester#61861 02/03/0607:58 PM02/03/0607:58 PM
Sounds like there's voltage potential between neutral and ground. Your common plug tester lights between hot & ground, hot & neutral, and neutral & ground... the neutral - ground light usually shows reverse polarity..
I'd try checking the voltage again under load.. You might discover a high impedance connection on the neutral and your tester may be displaying backfed voltage..
Re: Strange reading on plug tester#61862 02/03/0608:04 PM02/03/0608:04 PM
Voltages normal on L-N, L-G, N-G. No load on ciccuit the house is vacant. no furniture in house. The two receps are one in each of two differernt bed rooms. Both are at end of the circuit with only the hot neutral and ground from a 12-2G romex on end. the other recepts in the bedrooms read normal for a old house with a mixture of new romex and knob and tube wiring.
edited for spelling [This message has been edited by nesparky (edited 02-04-2006).]
[This message has been edited by nesparky (edited 02-04-2006).]
Re: Strange reading on plug tester#61865 02/04/0608:33 AM02/04/0608:33 AM
I ran into this at my sister's house once. It seems that she had a 240v window a/c unit put in and an electrician had changed the circuit for the recptacle under the window to 240. He had disconnected the receptacle downstream but didn't think about the one behind the china closet. I asked my sister if the lights in the china closet worked, and she said the last time they tried them the lights got real bright and then the bulbs burst. I wonder why
Re: Strange reading on plug tester#61866 02/04/0608:53 AM02/04/0608:53 AM
I had an open neutral upstream once that gave me that reading. It was part of a network and it fried the radio that was plugged into it. Luckily it was the first box over which tested normal. The neutral wire popped right out of the wire nut when I pulled that duplex receptacle out. Therefore: the neutral coming from the outlet with the problem was open and should have had 120v. to ground.