Some noise disturbance between Neutral to Ground

[marcosgue]

This a new commercial building with 208Y120V, 3Ph lighting panel I've already checked voltage
AB 208V AN 120V
BC 208V BN 120V
CA 208V. CN 120V
Neutral to Ground in continuity test makes noise disturbance, is this effect normal in the panel? I checked other panel is the same effect N-G.
What possible cause this effect?
I'm thinking there's a problem with the proper Neutral installation in somewhere.
Is this event cause to trip some breaker?
Any suggestion to fix is very appreciate

 

[infinity]

Can you describe in detail what you're calling a noise disturbance?

 

[marcosgue]

Well actually IDK is the proper term to describe what I'm hearing, but when I'm taking continuity test between N-G there's a some kind of buzzing like a persistent vibrations sound that make me thinking with something wrong with the proper Neutral installation.
I take off some branch wires from the panel and still this efect happen.

 

[Little Bill]

Well actually IDK is the proper term to describe what I'm hearing, but when I'm taking continuity test between N-G there's a some kind of buzzing like a persistent vibrations sound that make me thinking with something wrong with the proper Neutral installation.
I take off some branch wires from the panel and still this efect happen.

Are you using the audible setting on the continuity test? Some meters have an audible alarm to show continuity so you don't have to be looking at the meter. There would be continuity between N & G, so you would hear something if your meter has this feature.

 

[don_resqcapt19]

Exactly what tester are you using and exactly what settings on the tester are you using? Where on the system are you measuring the voltage between the neutral and ground.? From what point to what point? Is the measurement being taken at the service equipment or another location?

 

[synchro]

There will be some AC voltage developed across N and G due to the voltage drop on the neutral when it is conducting current. The level of this AC voltage can be relatively small and still interfere with the typical continuity test that applies a low level DC current and measures the resulting voltage. And so I wouldn't be surprised if you hear a tone that's modulated by 120Hz or something similar to that, and which would probably sound like buzzing.
For a meter's N-G continuity test to work normally you would need to have all neutral currents be zero.

 

[marcosgue]

I'm using the regular voltage meter, first I took measurement with Klein and then with Southwire meter. I know the audible continuity sound beat in the regular meter, but when I test continuity between N bar to EGC bar is sound like buzzing vibration. The measurement being taken in a subpanel no service equipment involved

---

 

[hbiss]

You can't do that. Continuity or resistance measurements can only be made on an unenergized panel.

The sound you hear is probably your meter getting ready to burn up.

-Hal

 

[jaggedben]

It sounds to me like he's describing the noise my fluke makes when I accidentally use the continuity setting on conductors with voltage between them (which does not damage the meter, BTW). This should not usually happen between neutral and ground (unless perhaps you are testing somewhere a long distance from the main bonding jumper and there's a large load causing a lot of voltage drop on the neutral).

@marcosgue
What do you get when you test for voltage between N and G at the same point?

I would check that the main bonding jumper or system bonding jumper is properly installed and the neutral is not floating with respect to ground.

 

[jaggedben]

It could perhaps also be a sign of an open neutral.

 

[hbiss]

It could perhaps also be a sign of an open neutral.

More likely a sign of someone who doesn't know how to use a meter.

-Hal

 

[marcosgue]

I know the resistant and continuity measurement should be taking in unenergized panel and the panel in cuestion with this type of issue is no energize yet.
I checked all terminal connexions and they're good and the issue still persist, is there some way to fix this?

 

[infinity]

I checked all terminal connections and they're good and the issue still persist, is there some way to fix this?

Can you upload a short video clip of the test with this sound you're hearing?

 

[marcosgue]

I'll try

 

[ptonsparky]

I am not familiar with the meters involved.

We had Beha testers that would sound differently if the neutral had current flowing on it while checking for continuity to an EG. 60 hz hum. Basically no hum at the SE if properly bonded. There would also be no hum if the same test was taken at a 'sub' with an improperly bonded neutral. Branch circuit and feeder neutrals with a load tested to an EG would generate the hum. Slight VD would be my SEWAG. I believe the subsequent Greenlee testers had the same trait.

 

[retirede]

Since you state that “the panel is not energized yet”, either your meter has a problem or there is a prankster lurking about with his hand on a buzzer!

 

[jaggedben]

I know the resistant and continuity measurement should be taking in unenergized panel and the panel in cuestion with this type of issue is no energize yet.
I checked all terminal connexions and they're good and the issue still persist, is there some way to fix this?

In your original post you gave us voltages and now you say it wasn't energized. Which is it?

Energized or not, if the meter gives a proper continuity reading on other stuff (touching the probes together, or both ends of a spool of wire) and it doesn't between N-G in the sub, then either
1) the neutral or the EGC to the sub is broken
Or
2) there's some kind of current or voltage that wants to flow from one to the other

 

[ptonsparky]

Check the voltage between neutral and EG at your sub.