GFI's?

[oneknight]

Today I drove the coach to get fuel, and to Speedco for an oil change.

When I got back, I noticed the Trav'ler wouldn't power up.
I looked in the right side (inverter) breaker panel and saw both the Living Room and Kitchen GFI Breakers were popped. I reset them and they popped again.
The Magnum panel indicated "inverting" as it should.

I plugged the coach into shore power, and I was able to reset the breakers and everything is normal.

I'll unplug again tomorrow and test, but does this ring any bells with anyone?

[jobobjet]

No help here but you are not alone. I have been trying to isolate this issue for a couple of months now. So far, I can't reproduce the problem.

[TurboDaveTX]

Had a similar problem earlier this month. At first I thought it was a breaker, but found the GFI kicked. Reset it and it kicked again. Unplugged everything on that line and it kicked again. Only thing in that line was USB charger outlet. No such outlet was available in the area we were in, so I replaced it with a standard 15A outlet. Problem solved! Ordered a replacement USB outlet from Amazon and installed it when we returned home. USB outlet works with no GI kicking. Don’t know if there is a way of checking a USB charger outlet for ground faults!

[shiggs68]

GFCIs will not reset if no power is being applied. You need a meter to verify the 120vac is actually coming from your Inverter. Also, your Inverter may have a breaker on it that needs reset.

[oneknight]

I found time to do some testing today.

When I unplug from shore power, the 2 GFI breakers in the inverter circuit panel trip.
Today I'm able to reset them while unplugged and they stay reset.
Other breakers in this panel are not affected, the microwave isn't losing it's time, the fridge doesn't blink, The inverter inverts, nuttin else wrong.

[oneknight]

I did some further testing on this today, and got out my voltmeter.

The inverter is working fine.

I have 7 volts AC nuetral to ground on every outlet (inverter and non inverter) in the bus on shore power.
Without shore power, I get 1.5 to 2 volts neutral to ground on the outlet in the bedroom, it's the only one I could easily access that is on the inverter but on the tripped gfi breakers.

Something seems to have come loose. any ideas?

[nothermark]

In theory you should have no difference between neutral and ground. The generator has them bonded (connected) at the generator. The shore cord should have them connected at the socket along with a connection to a ground rod. That leaves the Inverter. Assuming it switches both the neutral and hot leads or has a neutral common buss I would be looking for a bad connection there.

It would help if you had a schematic of the Inverter or could call their help line with your problem. If you can do that I would tell them what you found and see if they have an answer. I'm hesitant to tell you to just connect neutral to ground as the Inverter might have a current sensor in the return side of the AC line. Shorting that out might not be a good idea. In fact it is probably a bad idea assuming it is there.

[Turbojack]

I agree that there should be no voltage between neutral and ground. I would first go to the pedestal and see if you have a difference there. If there is a difference there I would get where you are staying's owners involved so they can get the problem fixed before someone dies of electrical shock.

On a side story I have a friend the owns a campground in Bolivar Texas. He has a customer tell him that he was getting shocked when he touched his RV when he was standing on the ground. My friend said he has seen the problem before and grabbed his volt meter to go help his customer. Turned out that the problem was coming from the power company. He called the power company and after talking to a few people he got someone that understood what he was saying. A crew from Energy came out and found that the salt air from the gulf had caused tracking between the neutral and the ground. They ended up washing down a few of their poles and the problem went away.

[nothermark]

The problem with large Inverters is that they also contain a second transfer switch that can interrupt the neutral as well as the hot leads. That isolates them from the bonding at the power pole.

[MRUSA14]

It could be the GFI outlet itself. I have had to to replace bad ones in my home. New outlets solved the issue

[oneknight]

OK.

In the main fuse panel, I turned off the breaker feeding the inverter.
the magnum 2800 switched smoothly from "float charging" to "inverting"
Nothing tripped. Everything still has power.

I turned off the 50 amp breaker on the shore pole. No change

I turned the inverter feed breaker back on. No change.

I turned shore power back on. No change.

I turned shore power off. The "living room" and "kitchen" GFI breakers both tripped and would not reset.
No matter what I did, these breakers tripped, until I restored shore power.

[voltdoc]

GFCI will trip if:

1) there is any difference in the power sensed flowing thru the hot conductor and the neutral conductor.
2) if the ground and neutral are shorted on the load side of the GFCI (because it creates the imbalance mentioned in #1)

Have you unplugged everything from every outlet and tested for normal behavior?

By code, shorepower electrical if wired properly bonds the Neutral and ground at the primary service panel. There can be only one place where neutral and ground are bonded. So when shorepower is disconnected the inverter takes over and also internally bonds neutral and ground together at the inverter. For further reading on how the Inverter does this see section 2.65 in the manual.

If neutral and ground are bonded elsewhere at the same time it can cause ground loops and possible erratic behavior of devices like GFCI.

Not easy to check, but one possibility is an additional ground to neutral bond exists in the breaker panel itself. This could be an accidental short as the neutral and ground buss bars are very close together in those panels (bottom of photo). Likewise, if the panels come stock with a ground/neutral bonding strap perhaps it wasn't removed.

BTW, I checked an outlet on my coach (which does not have any issue like this) and the neutral to ground voltage using an RMS meter was 3.2v. Not sure if that is relevant.

Good luck!

[oneknight]

Thanks Rob, everything helps, particularly from someone who owns a similar (identical) coach!

This affects BOTH GFI breakers in the inverter subpanel. The kitchen breaker all the time, the living room breaker most of the time.

It has not always been this way, this is new behavior.

What in the world could affect both inverter GFI circuits (but not affect the basement or bathroom GFI circuits in the other (main) panel)?

This is kinda a pain, as the coach is basically not useable unless I have shore power.
Also, the dishwasher drawer isn't locking during travel (since it doesn't have power)

[nothermark]

The voltage between neutral and ground bothers me. It tells me there is no bonding because a connection is open somewhere. That is probably what is tripping the GFCI's.