RV tripping shore power GFCI

[Knissone]

Hey all, first post here! I think I got it in the right forum, but feel free to correct me if I'm wrong.

I have my RV parked on the side of the house, and plugged into a GFCI circuit on the house, just a normal 15A circuit. This circuit powers only the RV, and a small low voltage landscape lighting system in the backyard. The GFCI does NOT trip when the RV is unplugged, so that landscape lighting is not the issue. So, when I plug in the RV, it will trip the GFCI, at seemingly completely random times. RV is a brand new 2023 Vortex / Geneses Supreme, and I've replaced the factory charger and inverter system with a full Victron suite. I can't quite seem to remember if I had this GFCI tripping issue on my older trailer before this one, but this GFCI tripping was/is a problem both before and after I did the Victron installation. Even with the Victron system set to "Charge Only", meaning it only charges the batteries and does not pass 110V into the coach, it still trips. I've tried different dogbone adapters, different extension cords, everything outside of the trailer, and know it did it on the trailer before and after the Victron so the trailer itself doesn't seem to be an issue. Now, going back that note of it tripping at random times; sometimes it will trip after 5 minutes, sometimes after 30 minutes, sometimes after hours or days, and sometimes (rarely) not at all. Whenever it happens and I can reset the GFCI, it doesn't trip again for another X amount of time. Given this, I'm kind of leaning towards the GFCI maybe having gone bad? It's an easy thing to replace and check, at least. It's also worth noting that I am in Southern California, so I'm not dealing with excessive humidity or rain that could introduce moisture to places it certainly shouldn't be.

Would anybody else have any other ideas? I've scoured the net and found that it's relatively notorious for trailers to trip GFCI, but I seem to be the only one to have this random time delay before it trips. Any tips appreciated!

 

[Ray-IN]

We'll forget history and deal strictly with the present problem. First turn off the charger function, observe results. If no change, go to main breaker panel and turn off main breaker, again observe results. if there is no change, the problem has to be that GFCI receptacle or the shore power cord.
I suspect you'll find the problem with the charger function. If anywhere in the RV the neutral and ground is bonded, that's the problem as I understand RV wiring.

 

[CharlesinGA]

You probably should unplug various devices in the RV that are plug in, such as the microwave, the fridge (especially if absorption, but even if a residential fridge), any chargers for phones/tablets, etc. If that does not help after a day or so, look at the water heater (assuming it is a tank type). Somehow isolate the 120v power to its heating element. Possibly the element is damaged or was left on without water long enough to damage it but not burn it out.

Charles

 

[Rene T]

You probably should unplug various devices in the RV that are plug in, such as the microwave, the fridge (especially if absorption, but even if a residential fridge), any chargers for phones/tablets, etc. If that does not help after a day or so, look at the water heater (assuming it is a tank type). Somehow isolate the 120v power to its heating element. Possibly the element is damaged or was left on without water long enough to damage it but not burn it out.

Charles

As a follow up, shut off your main breaker in the rv and all your 110 volt AC breakers and see if it trips. If it doesn’t trip, turn on one breaker at a time until you find the circuit that’s tripping it.
If it does trip even after you shut off the main breaker in your rv then the problem is between your rv breaker box on the shore power outlet or maybe the GFCI is bad.

 

[Gary RV_Wizard]

As others have said, you need to search out the cause of the ground fault. Something in the RV is triggering it, most likely something NOT on one of the RV's own GFCI branch circuit (the RV GFCI would also trip if it were on that circuit). Relatively common causes are wiring problems in the AC heater of an RV absorption fridge or in a converter/charger or inverter/charger. After that, it could be almost anything.

If the neutral wire is bonded to the ground in the RV's power panel, that would almost surely cause an external GFCI to trip immediately when the RV is plugged in. And one hopes that a new RV didn't have that kind of electrical system installation error, but stranger things have happened.

The fact that the trip occurs at random times suggests the problem is a device that has a thermostat or a timer.

 

[tlmgcamp]

What type of extension cord are you using and how long is it? If you are running 200 feet of 18 gauge (dollar store special) extension cord, there will be issues.

Extreme condition used for illustrative purposes, no offence intended

 

[John From Detroit]

I have read of Converters (Chargrs) that tripped a GFCI if the batteries were low.. Or if the batteries were full. or all the time.
Also as others have pointed out other circuits devices
Turn off ALL Brakers.. GFCI holds good
Turn on MAIN Holds good
Turn on one breaker.. if it holds turn that one off and turn on the next till it trips
When it trips. NOTE. the breaker. then turn it off. Reset and continue till you have either NOTED or Cleared all breakers.. IDentify the one that tripped it. IF converter.. Well there is hope.. but you may need to throw money.
If anything else figure out what trips it. Or just leave that breaker off.

 

[Gary RV_Wizard]

What type of extension cord are you using and how long is it? If you are running 200 feet of 18 gauge (dollar store special) extension cord, there will be issues.

Issues, yes, but GFCI tripping won't be one of them.

 

[Knissone]

Alright, finally got back to this today! I think I've got it narrowed down actually. It seems to be the microwave itself. I shut off all breakers including mains in the trailer, and went from there. Battery charger did not trip the outlet like many of you kind folks expected, so I continued turning on breakers one at a time. Finally got to the microwave circuit, and that seems to have done it. Tried it a few times to confirm, and it definitely was that circuit. Then I went inside the coach and unplugged the microwave from the outlet, and tried again. Everything was fine with the breaker, and found that the GFCI tripped when I re-plugged in the microwave. So it seems isolated down to the actual microwave unit.

While this isn't the end of the world for me, as I'm generally not actually using the trailer anywhere I'm plugged into a GFCI breaker (never seen a GFCI at a park 50A service, plus I do a lot of boondocking), does anyone have any further ideas other than just flipping the microwave breaker when I want to plug in at the house? It is a new trailer and all appliances brand new, theoretically could make a warranty claim if I needed to.

Thanks for everyone's input!

 

[OldWEB]

Did you ever try disconnecting the landscape lighting system in the backyard? Dunno how yours is wired, but if it was causing a small amount of current leakage and then the microwave just "pushes the GFCI over the edge" and trips it.
Just another thought...

 

[John From Detroit]

Ever have insects get into the RV... Some of them LOVE electronics (like the microwave control board) and end up.. Tripping a GFCI. A good wash with electronic safety cleaner (Get it at a BIG computer store like Micro Center or a Ham Radio Store like Ham Radio Outlet or DX Engineering or from an electronics place on line like all electronis.. NOT De-Ox-IT (That's for connectors not boards and more epensive)
or just pop in a new Microwave.. they are not that expensive and the RV microwave is really the same thign you get at Target or _____ (home appliance store) I mean my Dometic the only "RV" specific part was the front door.. it said Dometic.. not LG Everythign inside was LG. as in Lousy Goods (Though I was able to fix it)

 

[Kirk]

So it seems isolated down to the actual microwave unit.

I would be absolutely sure that it is the microwave that causes the problem and once I was I would address the warranty. It certainly does sound like the issue is the microwave but there is a very small chance that there is some problem in that outlet that is caused by inserting a plug into it. You could eliminate that possibility by just plugging an unused extension cord into it to verify that it still doesn't trip the GFCI.

 

[Gary RV_Wizard]

I'd say your test is conclusive and no, no suggestions for home use except to shut off the MW breaker or unplug it.

If you want to dig into it, you could open up the microwave and look around. I'd say odds are a stray strand of wire or maybe a dead insect or whatever shorting neutral to ground. It doesn't take much current to trip the GFCI , just 0.006 amps (6 mA). My money would be on the Mw power cord itself or its connection inside the Mw.

Or make a warranty claim against the microwave. Should be easy to show it fails by plugging it into any other GFCI.

 

[Knissone]

Alright, I'm back with more interesting and confusing bits!

Yesterday I was working in the trailer all afternoon/evening. After finding that the microwave was the culprit, I left that breaker off and went about my day. I went the next 5 hours or so with no issues. But, around 5:30pm it popped again, and I went back to exploring. Ended up with 3 more breakers shut off; The fridge (which had been running all day, not new), the water heater (which was running on propane, electric was not turned on), and the factory inverter return circuit which powers a plug in the bedroom, tv's, and the coffee pot, none of which were turned on. The battery charger function had successfully ping-ponged between bulk/absorption/float throughout the day without popping it, either. Nor was the landscape lighting plugged in at this point either, for those who may ask!

With those 3 additional breakers turned off, it lasted through the rest of my night before I turned in and I figured it was good to go. When I checked this morning, it ended up popping the GFCI again at about 2:45 in the morning. So, that time it had lasted about another 5 hours before popping. Before closing up shop for the night, I'd turned off the 12V disconnect, too, so nothing in the trailer was turned on in terms of thermostats or fridge or water heater or anything that might be the culprit for the time delay.

So far as I can tell, only 2 things changed when the GFCI started popping again in the evening. The sun had gone down, so solar panels weren't contributing any more, and the outside temperature had dropped (mind you, I'm in SoCal, so by that I mean it dropped into the 50's, nothing really substantial).

Sooooo here I am to ask again, anyone have any other ideas? I'm probably just going to spend 15 minutes replacing the GFCI outlet at this point, just for fun and see if it makes a difference. Beyond that, this whole thing just seems so confusing!

Other answers from past questions:

Did you ever try disconnecting the landscape lighting system in the backyard?

Yep! That part seems fine. Nothing ever trips unless trailer is plugged in. Trailer plugged in without landscape lights still pops it.

Ever have insects get into the RV

Fairly certain no. Never had any evidence of it, and unit was bought brand new 9 months ago. Not to say it's impossible, or could've been an issue sitting on the dealer lot or anything.

What type of extension cord are you using and how long is it?

Nothing that should be an issue; using a 50' 12/3 outdoor cord. Also, I've left the trailer plugged in for weeks, and just turned the Victron unit to "off" (doesn't pass through A/C, charge the battery, etc. Does absolutely nothing, essentially a disconnect from the shore power) and it never popped.

 

[John From Detroit]

Oh one caution if you decide to open the microwave and look about for insect or wires that should not be touching.

SHARP EDGES on some of them.. use caution.

 

[Kirk]

Sooooo here I am to ask again, anyone have any other ideas? I'm probably just going to spend 15 minutes replacing the GFCI outlet at this point, just for fun and see if it makes a difference. Beyond that, this whole thing just seems so confusing!

It wouldn't hurt to try changing out the GFCI outlet and at this point I might do that too. They do occasionally fail. The thing that makes this sort of problem so difficult to find is that it takes so little to trigger it opening. They typically trip with only 0.005a difference between the hot and neutral leads.

 

[Gary RV_Wizard]

Sooooo here I am to ask again, anyone have any other ideas? I'm probably just going to spend 15 minutes replacing the GFCI outlet at this point, just for fun and see if it makes a difference. Beyond that, this whole thing just seems so confusing!

Changing the GFCI outlet eliminates one possibility, even though its no longer a likely source of problems (GFCI quality is vastly improved from decades ago). Some other possibilities you could eliminate are the shore cord and any other wiring between RV and the GFCI outlet. A slight wiggle or the cord or a change in temperature could shift a strand of wire just enough to short neutral to ground. A new plug on the shore cord, and careful inspection of the cord connectors at the RV side would be worth it, I think.

It appears there is an intermittent fault somewhere in the shore cord or the RV. That makes turning off breakers an unreliable test. You don't know if the breaker shutoff fixed the problem or not, at least not immediately. Looks like it takes at least 24 hours before you can have much confidence.

 

[TwoHuskies]

I have the same issue. It was mentioned on another forum that tripping a breaker for a device breaks the hot connection but neutral and ground wires are still intact. You don't need any hot current for an impedance trip. This got me thinking about removing the breaker and capping the wire ends. Overkill? Perhaps, but tried many things. I will add this issue has occurred at several commercial (covered) storage facilities. I had all breakers tripped except main and inverter.

 

[Hvactech]

Trip your GFCI in the RV. Two GFCI's don't like being down circuit of each other.

 

[Kirk]

wo GFCI's don't like being down circuit of each other.

You can't share the neutral on the output of the GFCI. It must only go to the outlets being protected. If you try to share this neutral your GFCI will not work and will trip immediately. You can daisy-chain GFCIs if you connect them properly. They will still protect just fine.