Potentially Lose Neutral?

[Scottybars2288]

I have 800 amp services on the end of each building. each with 18 meters 1ph 120/208 125a-
one with an additional house meter, 3ph 4w 120/208 225. I noticed in the house panel and in the 125 amp 1ph panel, i’d have straight continuity between the neutral and ground, as I should. Once I turn on the lighting circuits the the continuity on my meters sounds like it comes and goes, like something is disrupting it or it’s loose. Comes back when lighting is turned off again. Continuity between neutral and ground at the service remains even while everything is energized, unlike the panel. my feeder connections are tight and neutral bonded in the main cabinet. From each service I have a UFER ground and a 3/0 copper to 4” underground water pipe.

 

[LarryFine]

You have a poor connection somewhere. Try taking fall-of-potential readings from point-to-point.

For example, look for voltage between the service neutral and the faulty panel's neutral.

 

[Scottybars2288]

You have a poor connection somewhere. Try taking fall-of-potential readings from point-to-point.

For example, look for voltage between the service neutral and the faulty panel's neutral.

i’ve checked all the feeder terminations and they’re good. I was hoping it would be on the power company but like i said within the house meter itself, I have continuity all the time. I dont know how it would be any of the branch circuits either unless i’m wrong.

 

[LarryFine]

The current of the branch circuits is exposing the problem, but not causing it, per se.

There is voltage between points where there shouldn't be an, a.k.a voltage drop (er, voltage rise?)

 

[Scottybars2288]

The current of the branch circuits is exposing the problem, but not causing it, per se.

There is voltage between points where there shouldn't be an, a.k.a voltage drop (er, voltage rise?)

it makes sense, I just have no idea where on my end this would be. All the bus in the meter banks is torqued, (snapped via manufacturer bolts) and i’ve checked the feeder and subfeed terminations. Is there anything else it could be or could it be the secondary neutral?

 

[LarryFine]

it makes sense, I just have no idea where on my end this would be. All the bus in the meter banks is torqued, (snapped via manufacturer bolts) and i’ve checked the feeder and subfeed terminations. Is there anything else it could be or could it be the secondary neutral?

That's why I'm suggesting FOP testing instead of visual inspections.

If you measure between the service neutral and the problem neutral (while under load), there must be a voltage difference. You just keep narrowing it down until you find the bad splice or connection.

So, even if you need a length of wire, measure for any voltage between the service neutral and the neutral where you're having the fluctuating readings. If you have that, you can find the problem.

It could be as simple as a wire in a lug, and there's voltage between the two, even though they feel tight.

 

[Scottybars2288]

That's why I'm suggesting FOP testing instead of visual inspections.

If you measure between the service neutral and the problem neutral (while under load), there must be a voltage difference. You just keep narrowing it down until you find the bad splice or connection.

So, even if you need a length of wire, measure for any voltage between the service neutral and the neutral where you're having the fluctuating readings. If you have that, you can find the problem.

It could be as simple as a wire in a lug, and there's voltage between the two, even though they feel tight.

makes sense, i’ll give this a shot