Bizzare shore power over voltage?

[birdhunter]

I am fairly handy with electricity but I am stumped on this one: I am plugged into 50 amp but I am seeing up to 130 volts on one leg on my AC feeder panel (as well as the readout on my Progressive EMS which is cutting the power when it hits 131). The voltage varies as loads change. As the one leg goes up 130, the other drops down to a 108! It seems to do it the most when the charger on my freedom 458 comes on initially. Is there anything in the coach system that can raise the shore power voltage that my coach instrumentation is seeing? I would think that the actual shore power would have to be varying, but perhaps it's something in the coach. I have never seen anything like this and it's beyond my expertise, so if anyone knows more about these things I would appreciate some ideas. I tried flipping all the breakers one by one but it doesn't seem to make a difference. If I unplug from the shore power and put my multimeter on both legs at the receptacle it's at a hundred and twenty volts.

Rich 2002 Magna

[monitormix]

That's a very typical symptom of a loose neutral either at the pedestal plug or entering the panel. Could even be upstream. Without any load the voltage between the 2 phases should look normal almost.

[birdhunter]

I think it has to be something in my Magna causing this since my neighbor is plugged into the 50 amp outlet right above mine and the outlets inside his coach are at 120 volts. As loads increase on one leg in my coach, the voltage goes up on the other. What could be causing this?

Rich 2002 Magna

[monitormix]

Also, when you meter across both hot legs at the pedestal are you seeing 240VAC.

[monitormix]

Originally Posted by birdhunter

I think it has to be something in my Magna causing this since my neighbor is plugged into the 50 amp outlet right above mine and the outlets inside his coach are at 120 volts. As loads increase on one leg in my coach, the voltage goes up on the other. What could be causing this?

Rich 2002 Magna

If your neighbor plugs into your outlet is his coach stable? If so, that would eliminate the receptacle.

In that's the case you need to see if the neutral has become loose on the line side input of your Progressive surge protector.

[Old-Biscuit]

Loose neutral Connection......

Inside power pedestal
Inside transfer switch
Inside Main AC Power Panel


Loose neutral connection........tighten all of YOURs in your rig
Have CG check/tighten inside power pedestal connection on 50A receptacle IF it does same when neighbor plugs his rig in to test

[Burfman]

Originally Posted by Old-Biscuit

Loose neutral Connection......

Inside power pedestal
Inside transfer switch
Inside Main AC Power Panel


Loose neutral connection........tighten all of YOURs in your rig
Have CG check/tighten inside power pedestal connection on 50A receptacle IF it does same when neighbor plugs his rig in to test

Agree with Old-Biscuit and others as too the problem... If you have the power reel check those connections, transfer switch, main bus bar at the breaker panel. Many times without a load the VOM will show proper voltage. Once you load it up the voltages go nuts.... Good luck and make sure you find the problem.. Loose connections can cause major problems...

[birdhunter]

I have checked everything in the coach. This problem does not occur when running off the generator, so I do not believe it can be the AC breaker panel in the coach. It appears to be a bad neutral somewhere in the shore power here at my friends ranch. An electrician is coming tomorrow snce I do not have the equipment to check that out beyond the receptacle. The only other suspect is something inside the male plug at the end of the Glenniding shore cord. I will have him check that out although it looks fine.

[twinboat]

Don't discount the MH wiring just because it doesn't happen on generator power.

Your generator may not be a 240 volt unit. It may have 2, 120 volt, same phase, outputs.

The output also doesn't go thru part of the transfer switch, power cord or reel.

[jwmaustin]

From my old days testing I always keep in mind that my test equipment can be wrong. You gauges can read incorrectly sometimes and it can be related to noise on the line, a faulty meter, etc.

[phays]

My EMS is wired before the transfer switch and therefore only show what is going on with shore power. This is contrary to what my electrical schematic shipped with my coach shows. So on my coach, the generator does not go through the EMS. I would first suspect the pedestal. Also, it is the most accessible.

As stated before, voltmeter testing without a load can be misleading. The fact that you only see the problem after the charger turns on and puts a load on the line indicates the you should be testing the connections with a load.

[birdhunter]

Originally Posted by twinboat

Don't discount the MH wiring just because it doesn't happen on generator power.

Your generator may not be a 240 volt unit. It may have 2, 120 volt, same phase, outputs.

The output also doesn't go thru part of the transfer switch, power cord or reel.

It's an 8000 watt quiet diesel. I think it does have two 120 volt legs. But the gen has to go through the transfer switch. My coach is wired from the factory with the surge protector downstream of the transfer switch. Wire number 105 goes to the surge protector which is now a Progressive EMS.