broken neutral

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hole snipe

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I had a trouble call at a detached garage that is fed with uf cable. The customer lost his lights and everything out there. I checked the hot leg to equipment grond and read 120v. Then I checked hot to Neutral and also read 120v. But when the neutral is connected to the loads, they don't respond. I flashed the twisted neutral loads to equipment ground momentarily, and bingo! everything worked. It was obvious that There was a break in the neutral in the earth or a bad splice. I ran out of daylight and have to go back tomorrow morning. My point...why was I reading potential from my ungrounded conductor (hot leg) to the supply neutral and it doesn't work the load. A break?? That is my assumption.
 
My point...why was I reading potential from my ungrounded conductor (hot leg) to the supply neutral and it doesn't work the load. A break??

Probably because your high impedance meter was reading between the ungrounded conductor and some very poor ground that probably exists at the break in the grounded conductor.
 
Bob, Thanks. I think you are right. It probably has enough earth potantial for a meter read but nothing to complete the path with a load on it. I will find it Tuesday and let you know how I made out.
 
Snipe, this is one reason I prefer a solenoid-type tester over a volt-meter: it presents a load.
 
LarryFine said:
Snipe, this is one reason I prefer a solenoid-type tester over a volt-meter: it presents a load.
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Sure wish I had one today. Got a final for a marina fuel system I repaired. The inspector was looking over the relays I used for the E-Stop and switching neutral requirements and when we checked to the "switched neutral" (from an ungrounded conductor) we got 120-volts. Looked like a grounded neutral, so we tore the control box apart trying to find what was grounded. I finally convinced the inspector the reading was because of the meter. I ohmed the neutrals to ground and got an open reading where when I was using the volt-meter I was reading 120-volts.
 
I own countless multimeters, clamp-ons with voltage capabilities, ect... but when all I want to know is energized or not energized and some trouble shooting, give me a wiggy.....I can feel the power, no looking.
 
brian john said:
I own countless multimeters, clamp-ons with voltage capabilities, ect... but when all I want to know is energized or not energized and some trouble shooting, give me a wiggy.....I can feel the power, no looking.
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Dittos -- and some of mine have Dwell and Tachometer on them as well :)

I was given a wiggy (?) last December because all my meters were back home and I wasn't about to buy Yet Another Meter (I did anyway, but I digress) and immediately fell in love. Mine makes a nice buzzing noise and has a neon light that lights up, so it's really easy to tell when the circuit is energized. And it never needs batteries. Oh, and it has yet to die from being left out in the rain. Major plus.
 
tallgirl said:
Mine makes a nice buzzing noise and has a neon light that lights up, so it's really easy to tell when the circuit is energized.
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It's my fav, but lets keep in mind that it indicates a voltage between points, not necessarily a voltage to earth. Two hot wires accidentally on the same phase could indicate no voltage, so I always double check between every conductor combination, as well as to ground.

If you have a solid reference ground, the wiggy is enough, but a non-contact tester can spot a hot conductor relative to Earth (the planet). The wiggy/extension-cord combo can't be beat for trouble-shooting eepecially when you have an open neutral.
 
That's right. I found the bad neutral connection. It was a J Box with a bad neutral connection. I cleaned it up and now it's back in commission. Thanks
 
More wiggy worship..... :rolleyes: It should be noted that this particular type of lost-neurtral could have been missed with or without one. This type of 'only under load' problem happens to varying degrees. Some will be picked up by it - some will not. Sometimes it takes a much larger load for the drop-out in relevant voltage to be seen. The small load of the soloniod in a wiggy can sometimes not be enough - sometimes it takes half the buildings loads for it to be enough... Reason being that if a neutral, or even a hot had say a contact in a lug or such, the relitive area of that contact patch might be say ~ the same area of a #14 wire - a wiggy would not catch that untill the load was much higher ~ 50A. The only way you'll find that one without visually seeing the effects of that type of condition on the wire, (Blackened wire, melted insulation) would be with a thermometer. One more great troubleshooting tool - that if you do a lot of it - you should have one.

FYI I own four meters, one is a wiggy, and I haven't touched it in years.
 
e57 said:
More wiggy worship..... :rolleyes: It should be noted that this particular type of lost-neurtral could have been missed with or without one. This type of 'only under load' problem happens to varying degrees. Some will be picked up by it - some will not. Sometimes it takes a much larger load for the drop-out in relevant voltage to be seen. The small load of the soloniod in a wiggy can sometimes not be enough - sometimes it takes half the buildings loads for it to be enough... Reason being that if a neutral, or even a hot had say a contact in a lug or such, the relitive area of that contact patch might be say ~ the same area of a #14 wire - a wiggy would not catch that untill the load was much higher ~ 50A. The only way you'll find that one without visually seeing the effects of that type of condition on the wire, (Blackened wire, melted insulation) would be with a thermometer. One more great troubleshooting tool - that if you do a lot of it - you should have one.

FYI I own four meters, one is a wiggy, and I haven't touched it in years.
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after i blew up my third pair of dykes because of false readings i took my 1/2 inch emt bender and used it like a 9 iron to launch it back where it came from. that little liying bastard.
 
tonyou812 said:
after i blew up my third pair of dykes because of false readings i took my 1/2 inch emt bender and used it like a 9 iron to launch it back where it came from. that little liying bastard.
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oops my first boss would call an emf detector a widge
 
Love my Knopp solonoid testers. But one comment. If you are working on controls for any type of conveyor system, be careful of the solonoid testers if you randomly check components. The solonoid testers can present just enough load to pull in coils that can start up motors "sometimes". A digital will be safer to use for that type of troubleshooting. And of course everybody knows about the 600 volt limitations, right?
 
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