Voltage on Neutral Wire

travis13 said:

So me and my Jman got into a HR box with 2 circuits. He turned off the breakers and undid the joints. There was a load on the neutral when he undid the joint. I put my ticker in the box and was picking up voltage on the neutral. We used a meter and got 230v. This was on the neutral wire that would be continuing downstream, not back to the panel.

What could cause this? Isn't the neutral supposed to have no voltage on it? Just the unbalanced load? Considering that everything is properly bonded at the transformer?

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MWBC = don't be taking neutrals apart if you don't know what's connected to them!

Lesson #2: How to find the equipment that got destroyed? AKA "What's that smell?"

So by undoing the neutral, if anyone had tied something in downstream and shared that neutral then you could read voltage correct? Since the joint is broke and the potential to ground has been removed?

A true neutral will have no voltage on it.. but what we usually call a neutral (because it's the white noodle) is really just a return for the hot conductor. It's the load side of the hot conductor. If you open that while voltage is still being supplied on the line side, you can let the smoke out of electronics.

travis13 said:

So by undoing the neutral, if anyone had tied something in downstream and shared that neutral then you could read voltage correct? Since the joint is broke and the potential to ground has been removed?

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Correct....if you unplugged or disconnected every load that the neutral is connected to then it will be dead with the exception of possible phantom voltage readings.

If you touch that neutral, you will not be too happy.

Why did your journeyman undo the neutral joint if there was a load on it?

travis13 said:

So me and my Jman got into a HR box with 2 circuits. He turned off the breakers and undid the joints. There was a load on the neutral when he undid the joint. I put my ticker in the box and was picking up voltage on the neutral. We used a meter and got 230v. This was on the neutral wire that would be continuing downstream, not back to the panel.

What could cause this? Isn't the neutral supposed to have no voltage on it? Just the unbalanced load? Considering that everything is properly bonded at the transformer?

Click to expand...

I don't know whats causing the problem, but I do know never, never, never open a neutral with the power on if it's multi wire branch circuit. You could possibly send a back feed through other appliances connected to the circuit and BLOW UP anything connected to the circuits. I've seen it happen by mistake! Pulling a splice out of a box, one neutral a little shorter than the others, splice not tight (spliced by others) and it pulled out of the joint. POOF! Can be a very expensive lesson!

I think you guys are over looking his question here. His journeyman turned the circuit breakers off for the circuits they were working on, the neutral somehow still had current on it. Normally one would assume, I know how to spell it that's why I don't do it anymore, the breaker is off so everything is safe to work. They didn't realize until they unspliced the noodle that current was flowing on it.

His question is what could be some causes for a load on the neutral, when the circuit breaker is off for the circuits in said junction box?

I'm thinking it is tapped off somewhere else, hidden junction box or splices. Is the power on the neutral coming from the panel or from out at the next box in line? If it's in the ceiling someone could of stole the neutral for anything.

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Travis, Is this a residential service 240/120 VAC?

240 VAC to what ground NOT FEASIBLE.

Explain where or how he measured this voltage

FRunck

A true neutral will have no voltage on it.

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Not true, actually any neutral with a load on the system will have voltage on it (depending where you measure the voltage, when measured to the EGC. There is ALWAYS voltage drop on any conductor between the source and a load, the neutral is bonded at the main service or separately derived system, the further you get from this point, with load on the system there will be an increasing voltage due to the VD.

FrunkSlammer said:

A true neutral will have no voltage on it.. but what we usually call a neutral (because it's the white noodle) is really just a return for the hot conductor. It's the load side of the hot conductor. If you open that while voltage is still being supplied on the line side, you can let the smoke out of electronics.

Click to expand...

A true neutral with no voltage means no power. You cannot have power without voltage. Current does not flow without voltage.

What we usually call a neutral is usually a GROUNDED conductor. It serves the exact same purpose as a "hot" which is actually an UNGROUNDED conductor. It is "not a return for the hot", it is a current carrying conductor the same as a "hot", only it is grounded.

In alternating current circuits, the "hot" and "neutral" would change roles as the "return" 60 times per second in a typical circuit.

Good for you "Bad Electrician". Welcome to the forum.

travis13 said:

So me and my Jman got into a HR box with 2 circuits. He turned off the breakers and undid the joints. There was a load on the neutral when he undid the joint. I put my ticker in the box and was picking up voltage on the neutral. We used a meter and got 230v. This was on the neutral wire that would be continuing downstream, not back to the panel.

What could cause this? Isn't the neutral supposed to have no voltage on it? Just the unbalanced load? Considering that everything is properly bonded at the transformer?

Click to expand...

What is the system voltage? You measured 230 volts between which conductors? How many breakers did he open? Which joints did he take apart?

travis13 said:

So me and my Jman got into a HR box with 2 circuits. He turned off the breakers and undid the joints. There was a load on the neutral when he undid the joint. I put my ticker in the box and was picking up voltage on the neutral. We used a meter and got 230v. This was on the neutral wire that would be continuing downstream, not back to the panel. What could cause this? Isn't the neutral supposed to have no voltage on it? Just the unbalanced load? Considering that everything is properly bonded at the transformer?

Click to expand...

Think of a light bulb, 120 volt on one side and neutral on the other side if you disconnect that neutral it will become hot. It gets more complex but I think this is a better way of explaining it lol

It may have been a 277v neutral which could explain getting 230v to ground, maybe.

It looks like somewhere else the neutral was used for a third(or more) circuit which was still on at the time. That, or more likely another neutral was accidentally spliced to the neutral you were working on(in some box downstream), creating a parallel path which went unnoticed until your J-man broke the splice. You could try clamp-metering the neutral before opening a splice, in a situation like that.

Spark Master said:

If you touch that neutral, you will not be too happy.

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The worst I ever got bit in my entire life, save 277, was from an open neutral serving a fluorescent ballast. That sheet hurt.

someone "borrowed" that neutral down stream and used it for another circuit. Most likely in a switch box because there was a dead end 3 way (fed from another circuit) in the same box and he needed a neutral for some reason.

five.five-six said:

The worst I ever got bit in my entire life, save 277, was from an open neutral serving a fluorescent ballast. That sheet hurt.

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I bet you holla'd like a little bish.

travis13 said:

We used a meter and got 230v. This was on the neutral wire that would be continuing downstream, not back to the panel.

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I feel the need to point out that there must be 2 points in order to get a voltage reading. You only mentioned one point, the neutral wire, so now we have to assume the 2nd point.

I would assume you tested to a known ground. But that 230V reading wouldn't work with most of our systems, so now I have to wonder if you were testing to a known hot.

So, if you want answers that are based on your site conditions, you must be more specific with your information.