# Weird voltage



## Bob Badger (Apr 19, 2009)

electron said:


> I checked the voltage which is phase A to neutral=0 volts, B to N=240 and C to N=240volts, from ground to neutral=120V. This is a sub panel being fed from a 100A panel, so what I did is star turning breakers off, one by one and when I turn off a 2 pole breaker feeding another freezer, the voltage went back to normal 208v between phases and 0V ground to neutral,


You have a serous issue with the neutral (like it's not connected) if your before and after readings are correct.


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## 480sparky (Sep 20, 2007)

Yep......... yet another classic open neutral.



(Are they not teaching this is class any more?)


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## brian john (Mar 11, 2007)

1. Neutral and A hase are crossed.

or 


2. The system's neutral is not grounded and A phase is grounded/shorted.


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## vizzolts (Sep 10, 2009)

My best guess is an open neutral in combination with A being shorted to N somewhere down the line from your 2 pole circuit breaker feeding the other freezer. Couldn't figure out how to factor in your 240V readings VS your 208V readings, unless that was just a typo.

If I'm talking out my ass I'd appreciate one of the old timers chiming in and correcting me.


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## BCSparkyGirl (Aug 20, 2009)

480sparky said:


> Yep......... yet another classic open neutral.
> 
> 
> 
> (Are they not teaching this is class any more?)



Well, they do up here in BC..........


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## electron (Sep 9, 2009)

I was tracking the freezer circuit and I found 2 J boxes with a few more circuits, at the second junction box the neutral was split to another circuit ( which I now is wrong since is a dedicated circuit should be by it self), but aside from that all joints are made properly, so I tried moving to another breaker and it when back to normal, but I still do not understand how is that happening.
The panel is being fed from a dry transformer delta 480, Y 208, but like vizzolts mention when I turn I getting readings of 240V to ground not 208V, I brought another multimeter just to make sure and I got the same readings, but something i didnt mention is that this panel is feeding more 110V circuits and all of them are "working properly" but still reading 110V between ground and neutral, and I try my gfci plug tester and all the lights came on, I test with my pen voltage tester and beep on the hot and on the neutral.
I am going to run a dedicated circuit for this circuit on saturday, but i still want to find out why is this happenig, plus we need to explain the customer what is going on, thank you for all of your advices. ​


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## vizzolts (Sep 10, 2009)

I'd double check the transformer hookup (turn off primary), verify correct grounding/ bonding, verify that you have a neutral and that nothing is shorted or crossed at your panel. Trace out all that branch circuit wiring that came off the old freezer breaker while the panel is still dead (maybe with the secondary conductors lifted so you aren't reading through the transformer). 

In fact the first thing I might do is kill power to the panel and ring out the conductors coming off that breaker or look through those J boxes. The answer is somewhere in there.


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## electron (Sep 9, 2009)

I just got back to that job and I was surprise whit all the mess, the circuit for the freezer was getting power from two different panels on each phase, the neutral was shared with a 110v circuit, in some other outlets the ground was used as neutral, etc. So we rewired 14 circuits and everything work just fine, thanks everybody for their responses


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