# Confused on Voltage Variance....



## working4aliving (Nov 12, 2012)

Hello everyone, i'm new here so please take it easy on me....
I'm a bit confused...and I will be getting some help from someone with a some more experience than me but this is what i have......

One Phase to ground 97V and the other phase to ground 147V
I figure, ok a loose neutral @ the service....POCO said nope.
So I do what i should've done to begin with.
I throw the main and take measurements again.
Now I get 120V from each phase to ground
Obviously the issue is within one of my branch circuits.

Ideas??


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## backstay (Feb 3, 2011)

working4aliving said:


> Hello everyone, i'm new here so please take it easy on me....
> I'm a bit confused...and I will be getting some help from someone with a some more experience than me but this is what i have......
> 
> One Phase to ground 97V and the other phase to ground 147V
> ...


I take it you are measuring before the main with the breaker open and closed. Did you check across the main to see if you have voltage drop? Just because your imbalance goes away with the main open doesn't mean it's a branch circuit. In fact I would say it isn't, that's just load showing up. If your measuring before the main, your problem is before the main.


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## wildleg (Apr 12, 2009)

sounds like the source, but . . . 

think about it. if you thought that it was one of your loads, and wanted to isolate the problem, what would you do ?. . . what would be the thing to do ? . . . . . (jeopardy music) . . . . . . 


- flip the breakers off on ea load one at a time and see if it changes the voltage ?



isolate the problem - divide and conquer


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## 480sparky (Sep 20, 2007)

If those are you readings at the main, the issue is upstream, not downstream.

The POCO may have only done a very rudimentary check and was not thorough at all. The open neutral may be in your panel itself, in the meter, at the weatherhead or even back at the transformer.


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## hardworkingstiff (Jan 22, 2007)

*Quick story*

2 years ago I was outside and noticed the PoCo truck pull up next door. Being the inquisitive (aka nosy) kind of guy I am, I asked my neighbor what was wrong. He told me they had been having light flickering problems. 

Well, the service guy checked and told them the power is fine (I'm watching/listening the whole time). Just as the service guy is getting ready to leave, I butt in and ask him if he would hold on a second. I turned off all of the branch breakers except the bathroom receptacle. I asked the homeowner to turn on the hairdryer in the bathroom while we (me and the Poco guy) took voltage readings at the service. 

No hairdryer, voltage is fine and balanced. Turn on the hairdryer and the phase the hairdryer was on dropped a couple of volts while the other phase went up a couple of volts. The phase to phase voltage stayed basically the same.

I informed him that this test indicated they (PoCo) had a neutral problem. He went to his truck, called into the office. A few minutes later he comes over with a meter looking device that plugs into the meterbase and tested for a degraded/missing neutral.

Later that day the PoCo had a sub out digging up the yard to fix the spliced/degraded neutral.

Bottom line, you need to test for yourself and don't trust the PoCo service guys, because they don't know everything.


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## working4aliving (Nov 12, 2012)

Wow, guys thanks for all the responses...........i was in fact measuring before the main and i see what you mean. It really had me puzzled because it just seemed like a neutral issue. 
I believe we will have them (POCO) called again and this time be a bit more "inquisitive".

I will keep you posted................

Thanks again!


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## denny3992 (Jul 12, 2010)

Had my poco come out twice to a customer before they fixed the open neutral problem... Thank god my customer didnt just turn the power on when poco left!


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## Spark Master (Jul 3, 2012)

therefore, you need to load the neutral on one leg, and only one leg to see what happens.

I would get 2 or 3 1500 watt heaters on 1 leg.


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## HARRY304E (Sep 15, 2010)

working4aliving said:


> Wow, guys thanks for all the responses...........i was in fact measuring before the main and i see what you mean. It really had me puzzled because it just seemed like a neutral issue.
> I believe we will have them (POCO) called again and this time be a bit more "inquisitive".
> 
> I will keep you posted................
> ...


So how did you make out?


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## MDShunk (Jan 7, 2007)

working4aliving said:


> Hello everyone, i'm new here so please take it easy on me....
> I'm a bit confused...and I will be getting some help from someone with a some more experience than me but this is what i have......
> 
> One Phase to ground 97V and the other phase to ground 147V
> ...


Yeah, no kidding? Tech tip: They always say that. You have a marginal neutral someplace. Find it.


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## N PHILLY KID (Mar 26, 2008)

*Confused on voltage variance*

I had something like this was open neutral in the service @ weather head
Reason I looked there was I put an am probe on the grounding electrode conductor and got 7 amps its a good way to to know of the neutral is open on the line side of the panel .


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## nrp3 (Jan 24, 2009)

So, if I hook the beast up to it at various points and start with 123v a side and the loaded side drops to 109v and the unloaded side goes up to 129v, same for either side tested, would that still be a bad neutral or more of a voltage drop? Mine will draw up to 100a a side. Flickering lights in various rooms. Worst with dimmers. Poco considering seperating services and adding a new shorter drop and transformer for this salon.


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## hardworkingstiff (Jan 22, 2007)

nrp3 said:


> So, if I hook the beast up to it at various points and start with 123v a side and the loaded side drops to 109v and the unloaded side goes up to 129v, same for either side tested, would that still be a bad neutral or more of a voltage drop?


If it was a voltage drop, the unloaded side would not see a voltage change if the neutral is solid. If you checked the line to line voltage during the test you would most likely see that the voltage stayed pretty close to the same (it will drop slightly for VD).

Based on what you posted above, you have a degrading neutral.


Edit: You may also have some degrading line conductors.

Is the service U/G or A/G?


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## nrp3 (Jan 24, 2009)

Overhead. Long run, 100yds, couple of splices, barn, daycare, also on same transformer


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## NolaTigaBait (Oct 19, 2008)

MDShunk said:


> Yeah, no kidding? Tech tip: They always say that. You have a marginal neutral someplace. Find it.


If I had a dollar for everytime they said that I'd have like 15 bucks...


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## 347sparky (May 14, 2012)

Had the same scenario at a church years ago. Tested A to B, 240 volt. A to N = 80v, B to N 160v. WTF? I tested it again and A to N was 118v, B 122v. Huh? Third time A was 150v and B 90v. Got a second meter with clips from the van and put both on the main. I could watch the voltage on A dropping while simultaneously watching B rising. It would hit about 80v then start climbing again while the other side went down. Took about 2 minutes to go full circle. There was a main breaker at the pole, shut it off and checked the incoming volts. No problems there. Underground service was losing it's nuetral.


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## hardworkingstiff (Jan 22, 2007)

nrp3 said:


> Overhead. Long run, 100yds, couple of splices, barn, daycare, also on same transformer


It would be easy enough to test the other services for the same problem. It might help you locate the degrading connection.


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## nrp3 (Jan 24, 2009)

The daycare isn't having trouble, she'd let me know. The barn owned by somebody else, who knows. That kind of narrows it down. These are long runs of #2 I believe and they were talking about bringing it up to 1/0 I think he (poco) said. The barn has the longest run and the least load, it'll get tagged onto the new transformer if they get around to it. I did that test after the main, before the main, at the meter.


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## hardworkingstiff (Jan 22, 2007)

nrp3 said:


> I did that test after the main, before the main, at the meter.


What were the results?


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## nrp3 (Jan 24, 2009)

Exactly the same


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## working4aliving (Nov 12, 2012)

HARRY304E said:


> So how did you make out?


Sorry for the late response guys...............you will NEVER guess what was wrong............Let's just say the POCO ended up fixing the problem. Yep, sure enough it was on their end.

Thanks again for all your responses.


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## hardworkingstiff (Jan 22, 2007)

working4aliving said:


> ...............you will NEVER guess what was wrong............


So what, you going to make someone ask or guess before you share?


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## Spark Master (Jul 3, 2012)

We all know what was wrong. Where exactly it was loosing the neutral, only you know that. But somewhere between the POT, and the ground rod. Prolly not at your weatherhead.


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## nrp3 (Jan 24, 2009)

Spill it. On mine they agreed in the next week or so to replace everything above the meter and add a transformer. Hopefully that cures it.


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## working4aliving (Nov 12, 2012)

According to what they told me at the transformer. Now i asked why that couldn't have been determined with the other trips, seems like that would be the first place they would look......
answer: "_Yah, I don't know man. It wasn't me so i'm not sure_"


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