Open Neutral voltage at campground

[SabaRocks]

We are staying overnight at a campground outside of DC now on our way north to get air conditioning since it is 100 degrees.

We have a Camco surge protector and circuit analyzer and it gave me an “open neutral” indication - first error I have seen. I had campground look at it and it is showing about 118v hot and 6v or a little more on neutral. Campground says that is some stray current and no big deal. That is with camper unplugged. Inside camper when plugged in, at outlet, I measure about 115v/8v. Are we safe to use this electricity? I did run A/C a bit to cool trailer off but unplugged it since we were going to be gone for a couple hours.

We are a little over a week in to a year long trip full-timing, so I don’t want to mess up this early in.

Thanks!
Jared
www.astreamcometrue.com
@astreamcometrue

[GMFL]

Some neutral-to-ground voltage should be present under load conditions, typically 2V or less. This is due to AC current variations. Some electronic devices “bleed” voltage back a noise and that could come from another camp site and be causing your problem.
There are a lot of connections and things running in a camp ground.

[Al and Missy]

Under heavy load conditions, the current in the neutral will raise its voltage with respect to the ground wire since the ground should be carrying no current. If you are a long way from the main power panel where the ground and neutral are bonded together, this can happen. The bad news is that the heavy load will also be lowering the voltage of the hot line. The hot line is going down, the neutral is going up - can lead to measured low voltage hot-neutral at your site. This can cause excess current, particularly in the air conditioner.

Measure the voltage from the hot to neutral. As long as this is at or above 115 volts under load you should be OK. I have a plug-in voltmeter that I leave in the outlet ear the door. Every time I come in I can look at it and check the voltage level.


Al

[SabaRocks]

Thanks, y’all. I feel better and also learned something today!

[jimfa440]

They need a better ground. Period. Back in the day I worked as a telecom engineer. We had a site in eastern NC that would go goofy in dry weather. It was a digital switch. In order to settle it down, someone would have to take a garden hose and soak the dead man.

[uncle_bob]

Hi

Assuming you are measuring both voltages to ground, phase is going to matter. 8V on the neutral can either add to or subtract from what's on the hot lead. That's why you *must* measure from hot to neutral. Otherwise you really have no idea what's what with a simple multimeter.

The real question is what happens when the A/C turns on. One would *guess* that the campground electric system is loaded at or past its capacity. You might see a pretty significant "droop" in the voltage. That's not going to make your compressor happy. It may trip out the surge protector with a "low voltage" alarm. If the neutral has an issue, it could. spike an "open neutral" as well.

Lots of variables .....

Bob

[waninae39]

yikes disconnect

it looks like a ground loop

these are more common on long legs

it can be deadly dangerous.

move to a better campground.
NOT SAFE

[Al and Missy]

If the load is perfectly balanced (it seldom is) between the two legs of a 120/240 circuit, the neutral current will be close to zero. Current in the neutral from an unbalanced load set will result in voltage drop on the neutral. As uncle bob says, if the 120V leg you are on is the one that is loaded more heavily the voltage on the neutral will subtract from the hot. If the other leg is loaded more heavily it will add. There should never be any current on the ground line and therefore no voltage drop so any current on the neutral will result in voltage with respect to ground.



In my opinion, 6V neutral to ground is not unsafe.


Al

[hhendrix]

I've run into this before too. One trick that might help if the water line is metal is to use one leg of battery jumper cable. Attach one end to the water line and the to the metal box of the post.