Inverter trips GFCI when plugged into 120VAC

[Kim Petersen]

Hey Fire Up, nice to hear from a brother on the road, I do have two RV 4 wire 50 amp receptacles to plug into at home, and have no problem with them. when I visit my daughter I plug into her outside outlet and run the furnace if it is cold enough. this also keeps the battery charged/tended. just last time her GFI tripped, so I had to find an outlet with no GFI protection, and it worked just fine. I have not found the ground fault, suspect a neutral to ground connection that should be isolated. My color is green, dodge ram 2500 toad, Ultra Classic and an ol Pan.

[dickb46]

Somewhere in the dusty closet in my mind I think I read that if you plug in a ground fault into an already gfci circuit it will trip the circuit

[dickb46]

Oh! Richard, the auto reset circuit breaker controls the ability of the alternator to charge the house batteries while driving. I found that out once on the road as it never charged the house batteries but does now!

[FIRE UP]

Originally Posted by dickb46

Oh! Richard, the auto reset circuit breaker controls the ability of the alternator to charge the house batteries while driving. I found that out once on the road as it never charged the house batteries but does now!

Huh?
I thought we were talking about GFCI issues on 120VAC shore power. And by the way, the OP's coach is identical to ours and that means, there is a continuous duty solenoid that's in the shore power compartment, that closes and provides the ability for the alternator on our coaches, to charge the house batteries. There is no "auto reset circuit breaker" that I'm aware of.
Scott

[Bobn1957]

Somewhere in my peabrain, there is a mention that the ground and neutral in an RV are not bonded and this would cause problems with the GFCI on the house or a portable generator. A GFCI works by sensing a difference between the hot and the neutral conductors (typically 15 mili-amps). The missing current is returning through the ground to the bond point.

[SaltLife]

Something is up since I tripped my GFI too... So it makes sense....

[gin7den]

I have the same problem with my 2006 Itasca. Started when It returned from extensive maintenance where I discovered the coach battery and wire leading to the solenoid were fried. I changed the solenoid wire and battery, but when I plugged into 110 power the GCI tripped. No coach circuit breakers are tripped. Checked the RV power cord and connection to the automatic transfer switch, but other than some minor darkening and moderate fusing of the positive cable wire, I see no problems. Will check the relay battery disconnect and converter next. Had the coach in a local RV repair and they report no issues with the 30 and 50 amp, but confirmed the 110 would pop the circuit and return the couch unfixed. Last time for them. Leaves me with a safety concern, so I am still working the issue. Any suggestions?

[bigb]

One thing to check is that all the neutrals are landed on the neutral bus on the 120 volt side of the power center. Someone on the Airstream forum had his converter replaced and when he got it home it would trip the GFCI, he attached a photo and the installer had landed the converter neutral on the 12 volt neutral bus! All the 120 volt neutrals (white) need to be on the same bus, all the bare or green 120 volt grounding wires need to be on a different bus and not connected in any way to the neutral bus (no bond) and all the 12 volt wires need to be on their respective bus with no connection to the 120 volt side. The 120 volt grounds can and should be bonded to the metal parts of the RV (including the 12 volt negative) but never bonded to the neutrals at any point.
Another point of an un-intentional bond can exist at the electric water heater element if equipped, or at the fridge 120 volt element if equipped, and can cause a ground fault even if not in use. In order to test, both the hot and the neutral to the heating elements should be disconnected.

[eyecando]

A 110 volt circuit typically consists of 3 wires. These are hot, neutral and ground. GFCI breakers trip for one of 2 reasons only.

1. The current in the circuit is exceeding the breaker trip point.
2. The current in the hot wire does not exactly match the current in the neutral wire.

A defective breaker is a possibility or maybe you are exceeding the trip point (amps) of the breaker because your RV is drawing to much current or maybe something else on the circuit in conjunction with the RV current is tripping the breaker.

The other more likely possibility is that the neutral and ground connections for one of your devices (refrigerator or furnace?) have the wires swapped or connected together. In that case, the current in the hot and neutral legs would not match and the GFCI breaker would be tripped. Everything would work normally on a non-GFCI circuit.

Grounding should not affect the GFCI breaker unless the ground was connected to the neutral somehow. The neutral and ground circuits must be independent. You could check for this by unplugging from the 110V circuit and using an ohmmeter to measure between the neutral and ground terminals. There should be no connection.

[eyecando]

Originally Posted by Kim Petersen

yup, did that, the non-gfci receptacle feeds the bus with no problem, and the meter registers between 2 to 5 amp draw depending on furnace and or refrigerator cycling. thanks. must be something in the bus, no other load trips the gfci receptacle that I plug into it, like a drill, or shop vac, etc. my problem is a wind storm damaged my roof so I have stored the bus and the only available power is a gfci receptacle.

First thing to realize is how a GFCI breaker works. It compares the current that goes out of the GFCI breaker with what comes back into the breaker. In other words, the current supplied from the hot lead must almost exactly match what comes back on the neutral lead. The GFCI does not look at the ground wire. Most likely failure point would be at any plugs including surge protection you are plugging into the circuit. The actual load on the circuit should have no effect as long as the amp rating is not exceeded assuming the GFCI is good.

Sounds like everything works normally when not plugged into a GFCI circuit.

Have any receptacles been replaced? Swapping the ground and neutral leads on a receptacle or anywhere else would cause this. Water or other contamination into the circuit could cause the tripping.

I would start by turning off all breakers in the RV to see if that eliminates the GFCI tripping. If you have some kind of surge protector plugged in, remove that also.

If the GFCI breaker continues to trip with all breakers off, that would point to a problem in your wiring to the RV. I would suspect the plug in that case and I would replace it.

With the RV unplugged and using an ohmmeter, measure the resistance between the hot terminal and the ground terminal. Next measure the resistance between the neutral terminal and the ground terminal. I would expect to see very high resistance values, probably at least 200K ohms. It only takes about 6 milliamps of current leakage to trip the GFCI device and that would correspond to 20K ohms or less. Realize the actual value of resistance could change with water intrusion. Ideally, the resistance values should be at least 1 megaohm or greater.

Probably last thing to suspect would be the transfer switch.

[bigb]

Originally Posted by eyecando

If the GFCI breaker continues to trip with all breakers off, that would point to a problem in your wiring to the RV. I would suspect the plug in that case and I would replace it.
.

Not necessarily. Switching off all the breakers will not remove a N-G fault which will still trip the GFCI. In order to isolate a N-G fault you must remove the neutrals from the bus, one at a time.
Just had one over at iRV2 that was tripping the GFCI with all breakers off. Instructed the owner to remove neutrals one at a time and they were able to find the offending circuit this way.

[Bobn1957]

Originally Posted by bigb

Not necessarily. Switching off all the breakers will not remove a N-G fault which will still trip the GFCI. In order to isolate a N-G fault you must remove the neutrals from the bus, one at a time.
Just had one over at iRV2 that was tripping the GFCI with all breakers off. Instructed the owner to remove neutrals one at a time and they were able to find the offending circuit this way.

The GFCI needs power to work if the breakers are off the GFCI is off as well!

[bigb]

Originally Posted by Bobn1957

The GFCI needs power to work if the breakers are off the GFCI is off as well!

Originally this thread was about a shore power GFCI tripping but that was over a year ago and others have joined in with GFCI issues so this thread is now getting muddled and confusing, and to add insult to injury the OP never came back to tell us what it was.

[eyecando]

Originally Posted by bigb

Not necessarily. Switching off all the breakers will not remove a N-G fault which will still trip the GFCI. In order to isolate a N-G fault you must remove the neutrals from the bus, one at a time.
Just had one over at iRV2 that was tripping the GFCI with all breakers off. Instructed the owner to remove neutrals one at a time and they were able to find the offending circuit this way.

Yes, you are correct. I didn't think about that possibility. But measuring the neutral to ground resistance at the plug end should indicate an issue with the neutral circuit.

At the residence, the neutral and ground circuits are tied together in the breaker panel, but there should be no connection between neutral and ground inside the RV.

[eyecando]

Originally Posted by Bobn1957

The GFCI needs power to work if the breakers are off the GFCI is off as well!

Yes, I agree, but the GFCI we are referring to is the external one from the residence or the campground and it would be energized.

[creativepart]

Originally Posted by bigb

Originally this thread was about a shore power GFCI tripping but that was over a year ago and others have joined in with GFCI issues so this thread is now getting muddled and confusing, and to add insult to injury the OP never came back to tell us what it was.

It started back in May when someone tacked their new issue on to a year old thread on a somewhat different topic.

I try hard to catch these and split them out and into new threads but didn't see this one in May.

I've read through the thread and considered splitting the thread into two parts at the May, 2023 post of gin7den - but, I feel too confused by the differences between the original thread and the turn it took in May.

This is a major reason we ask that folks start new threads with new questions. They do a search, find an old thread that mentions some similar topics and tack their new question on to the old thread.

So, I have not split this one into two to prevent even more confusion.

[bigb]

Originally Posted by creativepart

It started back in May when someone tacked their new issue on to a year old thread on a somewhat different topic.

I try hard to catch these and split them out and into new threads but didn't see this one in May.

I've read through the thread and considered splitting the thread into two parts at the May, 2023 post of gin7den - but, I feel too confused by the differences between the original thread and the turn it took in May.

This is a major reason we ask that folks start new threads with new questions. They do a search, find an old thread that mentions some similar topics and tack their new question on to the old thread.

So, I have not split this one into two to prevent even more confusion.

I can see how hard it must be to keep up with the different postings, you have a thankless job. One thing I have seen on some newer forums which helps is the original poster's posts are marked "OP" which helps, but I'm guessing that would take costly new forum software. Thanks for all you do though.

[SaltLife]

Originally Posted by bigb

I can see how hard it must be to keep up with the different postings, you have a thankless job. One thing I have seen on some newer forums which helps is the original poster's posts are marked "OP" which helps, but I'm guessing that would take costly new forum software. Thanks for all you do though.

I've seen Author too which helps alot...

[Ray,IN]

Originally Posted by Bobn1957

Somewhere in my peabrain, there is a mention that the ground and neutral in an RV are not bonded and this would cause problems with the GFCI on the house or a portable generator. A GFCI works by sensing a difference between the hot and the neutral conductors (typically 15 mili-amps). The missing current is returning through the ground to the bond point.

That is correct, they should not be tied together. The RV is treated like a sub-panel and should not be grounded. There is only one ground in a circuit..

Re-read the reply by bobB #28




If an RV has a EMS, it will trip the GFCI, as it sees an imbalance.
A side note, the new regulations for new installations in CG's require 30A or less receptacles to be a GFCI.

[bigb]

Originally Posted by Ray,IN

That is correct, they should not be tied together. The RV is treated like a sub-panel and should not be grounded. There is only one ground in a circuit..

Re-read the reply by bobB #28




If an RV has a EMS, it will trip the GFCI, as it sees an imbalance.
A side note, the new regulations for new installations in CG's require 30A or less receptacles to be a GFCI.

Ray,
As far as I know the GFCI requirement proposal was defeated and still only required for the 20/15 amp receptacle at the campground. In the first code cycle it was put on hold with a TIA and finally is was defeated for subsequent code cycles.
Not sure why the EMS would cause a GFCI to trip, never heard that before. I have a Progressive Industries EMS permanently installed on mine and I can plug into a GFCI with no issues. I have heard of inverters and converters causing problems though.