I know that GFIs can sometimes be a pain but they are a necessary pain. Here is the issue. Everything works great for days on end when I'm plugged into the garage GFI for pre/post trip like running the refrigerator, lights, etc. However, if I run the MH generator for any reason it trips the garage GFI. I have on other electrical issues with the MH.I do know that the GFI in the garage is pretty sensitive. House was built in 2007 and has no electrical issues. Just wondering what might be causing this.

I am not sure if I understand your comments or not...Are you saying while you are still hooked up to the house/garage 15/20AMP receptacle using a RV30-15A Adapter that when you fire up your motorhome installed generator you trip the breaker in the house/garage.I am also aware that the MH should have an active POWER TRANSFER SWITCH that would separate the trailer 120VAC circuits and the 120VAC shore power cable when the MH generator starts up. If you are truly backfeeding the house circuits I would expect the house/garage breaker to trip if the MAIN HOUSE/GARAGE circuit breaker is still bringing in commercial power for the house. You would be feeding the house electrical system with two separate 120VAC sources at the same time. Something has give up????IMO There is two things wrong with this type situation... The most important reason to always flip the house main circuit breaker when feeding the circuits with an external generator is to protect any electrical workers on the commercial side working on the lines or equipment near your house. They have no idea the line coming from your is ACTIVE being fed by your generator. This is why most house emergency setups all use a POWER TRANSFER SWITCH either manual or automatic when connecting an external generator to the house circuits. The other reason is you may be in big danger of having your external GENERATOR blow up on you. Obviously the commercial power feeding your house is much stronger than your external generator and guess which one will lose the battle... If I have misread your comments than disregard all of the above....I am no expert on this subject - just an Illinois Corn Field Plow Boy from Horse Creek country...Just my thoughts hereRoy Ken

Your transfer switch is trying to energize from the genset while there is power coming from the garage.You should be un-plugging the garage power or any shore power before starting genset.

enblethen wrote:You should be un-plugging the garage power or any shore power before starting genset.I agree it sounds like a bad transfer switch holding both sides on, but you shouldn't need to unplug from shore power to run the generator. After all that's what the transfer switch is for in the first place!

I would think it has to be the when transfer switch opens or closes the contacts to the shore power line is causing the GFCI to trip. I don't think you have a problem. Just The GFCI doing it thing. As posted above disconnect your shore power before starting Gen.

sch911 wrote:enblethen wrote:You should be un-plugging the garage power or any shore power before starting genset.I agree it sounds like a bad transfer switch holding both sides on, but you shouldn't need to unplug from shore power to run the generator. After all that's what the transfer switch is for in the first place!You do need to unplug or at least turn off the shore power before the generator picks up the load. It is an automatic transfer switch made to go to shore power first then genny if NO shore power available.At least that is the way it is on my Southwind

House GFI trips when I run MH generator | Good Sam Community

Gene_Ginny
Explorer
Sep 24, 2014
gatorcq wrote:
shore power should NOT be a GFI.
...
My shore power has been GFI for 8 years (when I am home). Only time it tripped was when I had an actual fault develop in the converter. I fixed the fault and the GFI is happy now.
vermilye
Explorer
Sep 23, 2014
ktmrfs wrote:
gatorcq wrote:
shore power should NOT be a GFI.

4 wire (50amp) Hot, Hot Net, Gnd)
3 wire (30amp) Hot Net, Gnd

and why should/can't shore power be connected to a GFI. doesn't have to be, but nothing prevents one from connecting the shore power to a GFI outlet and if connected it should function properly unless there is a fault.

Granted, not many 30A outlets or 240V (4 wire) outlets are GFI, but I routinely connect my 30A trailer to a 20A GFI outlet in the garage and it functions as it should. GFI trips on a fault but otherwise I'm powered up.
2X

And, you may run into campgrounds that have GFCIs on their 30 amp receptacles. Rare, but I've found 2 of them, both in Missouri State Parks...
ktmrfs
Explorer II
Sep 23, 2014
gatorcq wrote:
shore power should NOT be a GFI.

4 wire (50amp) Hot, Hot Net, Gnd)
3 wire (30amp) Hot Net, Gnd

and why should/can't shore power be connected to a GFI. doesn't have to be, but nothing prevents one from connecting the shore power to a GFI outlet and if connected it should function properly unless there is a fault.

Granted, not many 30A outlets or 240V (4 wire) outlets are GFI, but I routinely connect my 30A trailer to a 20A GFI outlet in the garage and it functions as it should. GFI trips on a fault but otherwise I'm powered up.
gatorcq
Explorer
Sep 22, 2014
shore power should NOT be a GFI.

4 wire (50amp) Hot, Hot Net, Gnd)
3 wire (30amp) Hot Net, Gnd
CA_Traveler
Explorer III
Sep 22, 2014
My Onan generators bonded the neutral and ground prior to the ATS. My Magnum inverter/charger bonds the neutral/ground AC output when inverting but not during pass through with it's built in ATS. So all is well.
ktmrfs
Explorer II
Sep 22, 2014
CA Traveler wrote:
mayo30 wrote:
How many pole is the transfer switch?Does it switch off the nuetral also in other words does it isolate the lines?Bet it doesn't.
Not switching the neutral would be a serious safety concern which no RV mfg wants.

All ATS units should switch the neutral and hot(s). All grounds in the rig should be bonded, ie no switching.

correct. However, most onboard generators when running bond the trailer neutral and ground together. Usually through the transfer switch, since the trailer neutral and ground by NEC code are NOT to be bonded together when connected to shore power.

and a ground/neutral bond downstream of a GFI WILL trip the GFI. GFI checks two things. One, is there a current imbalance between hot and neutral and is there a neutral/ground bond. NOTE: GFI do NOT check for current in the ground, just an imbalance between hot and neutral, which is assumed to be a fault and possible current flow through the human body.
john_bet
Explorer II
Sep 21, 2014
I have 21 years experience working with industrial size gen sets and automatic transfer switches that make the average RV transfer switch look like a normal relay. They can take a full load transfer without an issue, but I seriously doubt that the RV type can do it. The other issue you have when doing a transfer with a load is that there is a surge going back to the GFI when the contacts open that may cause it to trip. I do think that all RV transfer switches are no created equal. From what I have seen most are just two contactors of doubious quality to do the job.
sch911
Explorer
Sep 21, 2014
darsben wrote:
You do need to unplug or at least turn off the shore power before the generator picks up the load. It is an automatic transfer switch made to go to shore power first then genny if NO shore power available.

At least that is the way it is on my Southwind

No I've never had to unplug anything. Should switch between automatically.
CA_Traveler
Explorer III
Sep 21, 2014
mayo30 wrote:
How many pole is the transfer switch?Does it switch off the nuetral also in other words does it isolate the lines?Bet it doesn't.
Not switching the neutral would be a serious safety concern which no RV mfg wants.

All ATS units should switch the neutral and hot(s). All grounds in the rig should be bonded, ie no switching.
mayo30
Explorer
Sep 21, 2014
How many pole is the transfer switch?Does it switch off the nuetral also in other words does it isolate the lines?Bet it doesn't.