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Posted By: nesparky Strange reading on plug tester - 02/03/06 10:58 PM
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 ?????
Posted By: Dnkldorf Re: Strange reading on plug tester - 02/03/06 11:06 PM
Did you check with your meter L-N,L-G, and N-G and all these are correct?


Dnk..

[This message has been edited by Dnkldorf (edited 02-03-2006).]
Posted By: JoeTestingEngr Re: Strange reading on plug tester - 02/03/06 11:57 PM
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
Posted By: Lostazhell Re: Strange reading on plug tester - 02/03/06 11:58 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..

Randy
Posted By: Dnkldorf Re: Strange reading on plug tester - 02/04/06 12:04 AM
Lost, that makes sense...


Dnk..
Posted By: renosteinke Re: Strange reading on plug tester - 02/04/06 02:11 AM
When there is more than one problem, or the receptacle is falling apart, plug testers will come up with some strange readings.

They are a help- but not the cat's meow. At this point, just use it to tell you if you've turned off the right bresker....then pull out the receptacle and start checking things with a real meter.
Posted By: nesparky Re: Strange reading on plug tester - 02/04/06 04:54 AM
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).]
Posted By: Del Elec Re: Strange reading on plug tester - 02/04/06 12:33 PM
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
Posted By: Dnkldorf Re: Strange reading on plug tester - 02/04/06 12:53 PM
These receps don't come off a GFI recep somewhere, do they?

I've seen this once, but can't remmember the details. But I think, it was when I pressed the test button, and all three lights came on..


Let us know what you find..


Dnk..
Posted By: Ralpha494 Re: Strange reading on plug tester - 02/04/06 02:39 PM
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.
Posted By: Active 1 Re: Strange reading on plug tester - 02/04/06 02:50 PM
Had all light up once when I did some outlets at a factory. My first thought was oh no what did I do. Had some strange voltage readings too.

Turned out it was a problem with the B crew installing the transformer and panel. I did not do it or fix it but I think they forgot to bond the nutral and conect the G-rod.

Tom
Posted By: venture Re: Strange reading on plug tester - 02/04/06 04:39 PM
I had this happen once not lonag a go. It turned out to be a tripped GFCI down stream from the recptical, don't know why but reseting the GFCI solved the problem. Rod
Posted By: gfretwell Re: Strange reading on plug tester - 02/04/06 10:36 PM
The GFCI opens the neutral and if that doesn't "close" properly you get all sorts of strange things on an outlet tester, depending on downstream load.
Posted By: nesparky Re: Strange reading on plug tester - 02/05/06 02:32 AM
Was back at that house today. Found that a painer decided the inside of a junction box needed a lot of paint. Cover missing and half full of paint. Took me half an hour to clean out. Also found all the ground wires in the box but one together, the one not in was the one to the panel. So I had lost the ground back tothe panel. Also the bare ground was under a neutral wire nut just touching the neutral wires stripped end. Found 3 GFCI full of paint as well. None of those GFCI were on the bedrooms circuit. After fixing all of this every thing is now normal.


Now if I can just find that painter when I have a 3 foot piece of 3/4 rigid in hand [Linked Image]

editd for spelling

[This message has been edited by nesparky (edited 02-04-2006).]
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