Unbalanced Electrical -- 127 volts and 116 volts?

[Road-Chi]

After plugging into an RV park's shore power today, we noticed that the volts are not balanced, as shown in the pictures. One side is reading 127 volts while the other is at 116 volts (not balanced at 120 volts each). Also, the amp readings fluctuate between 0 and what we are actually using.
Should I be concerned?

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[TandW]

Shut off everything that is running. What are your V and A readings with nothing on?

[Road-Chi]

With everything off, the volts are 125 and 121. The amps are 1 and 1.

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[twinboat]

Yes be concerned. You have a bad or failing neutral . If it gets worse you will still start burning stuff up.

Call the park and get them to send out an electrician.
It could also be your rig. Bad plugs, loose connections and even cord reel contacts.

[TandW]

Could be a problem with park power. Or could be a problem with your wiring. You seem to have had a somewhat heavy load on only one leg when you reported in.

[K7JV]

Twinboat and TandW have good suggestions. In my actual experience, we have encountered several RV park pedestals that did not perform well. RV cable plugs get inserted and pulled up to as many as hundreds of times a year and not only can the "squeeze" weaken over time, but the physical jostling of the receptacles can allow deterioration of the connections on the back of the receptacle. Having the park check it out first is a great idea. A 14 amp current differential shouldn't pull the neutral that far "off center". There very likely is an unacceptably high resistance inside the pedestal, in the pedestal receptacle, in your pigtail plug, in your coach end plug, your transfer switch or your load center.

Actually, one way you could test at least some of the system would be to start your generator and let your coach transfer over to it. Then try to configure your loads so that one leg is loaded significantly higher than the other. You could do that by running the two of your HVAC units (assuming you have three) that are on the same leg, or running a space heater or microwave a cup of water. See how the voltage shifts if you can get 20 amps or more of unbalance. Let us know what you find.

Hopefully it will be a park pedestal problem and all will be made good.

[Road-Chi]

The park had the maintenance guy come to our site; he took the cover off the pole and measured 122 V at each side. This new picture shows the readout with the coach disconnected to the pole and our generator on and loads applied to Line 2.

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[Road-Chi]

Another picture with a higher load on Line 2 while using the generator

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[TandW]

So if there is a problem, it is on board. Why are you running an unbalanced load to begin with?

[brobox]

Reboot the Vega Touch with the 12v power switch. I would believe the park's tech with a voltmeter over the accuracy of the VT. My VT has been wrong more than once.

[Road-Chi]

The coach seems to be wired to create an unbalanced load. Almost everything we use routinely is on Line 2, such as the dryer, microwave, HVAC 1, HVAC 2, fireplace, toaster, and coffee maker. About the only things on Line 1 are the stove top, HVAC 3 (the back unit), and the dishwasher. Here is a picture with more load on Line 2.

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[K7JV]

Those are great pictures. Well done. A couple of thoughts. As a retired electric utility engineer, our guidance was to keep delivery to the service entrance of our customers at the nominal voltage, plus or minus five percent. At 120 volts, that would be a range of 114 to 126 volts. You are well within those limits with your 25+ amp imbalance in place.

Since the park did their inspection, have you tested that source again? It would be interesting to see if anything changed. If they didn't actually change anything out or re-torque some connections, there shouldn't be any change other than possibly the quality of the connection between your pigtail plug and the receptacle from removing it and re-inserting it.

I believe that you have eliminated two-thirds of the transfer switch as well as your load center from being a problem. You could still have a high resistance on your shore power neutral connection. If you get to that point, you could tighten that set screw. See my last paragraph below if you do decide to putz around in your transfer switch and contact any live connections or parts of the switch. And remember that most of what is in that box normally has dangerous voltages present whenever any power sources are connected.

It is not surprising that your coach's nominal and normal loads are not even. They were on our '06 Dynasty, too. It really isn't a problem as long as it isn't severe enough to cause excessive voltage on one of the legs or, even worse, to trip the breaker on the high current leg.

Later, if you feel you should, you could move a couple of loads in your load center to better balance your system. If you are the least bit uncomfortable doing this, or if you aren't 100% sure of what is hot and what is not, be sure to bring someone in with the expertise to help you with it.

[Road-Chi]

We rebooted the Vega Touch, and the readouts did not change. Though it is odd that the amp readings on the Vega Touch bounce between (for example) 14 amps and 0 amps while the device using those amps does not show any indication of a depletion of power, which may imply a faulty Vega Touch reading. It is confusing [emoji53]

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[twinboat]

Let's go back to another time you used your RV.
Did you have this kind of voltage differences ?

If not, something has gone wrong.