GFIC Outlet only works when plug-in to Shore Power

[NewToClassB]

We are new to Class B RV. We recently noticed on our 2022 Thor Tellaro 20A that the GFIC outlets only works when we connected to Shore Power. I tried plug in a phone charger with either generator turned on or just with inverter turned on and no power. Does anyone know why the GFIC outlets only work when connected to shore power and how to fix the issue? Thank you.

[HarryS]

Welcome. It would help to know that amp your shore power service is, what size generator you have. It's possible that your generator isn't big enough to power the entire rig, and if so, the manufacturer will limit what it can be used for. Same for the inverter. Look at your AC panel, what circuit breakers are on the main buss, and what breakers are on the sub panel. Likely the GFCI is on the main and not the sub panel.

[NewToClassB]

Thank you HenryS for your reply. I forgot to mention, GFCI outlets were working before with both Generator on or Inverter turned on. We just found out this issue a week ago when we were traveling in AZ. I plug in the shore power when we got home and found out GFCI outlets are working fine. It is hard to believe a cellphone charger will require so much power.

[16ACE27]

Time to do some more symptom verification:

It NOW works on SP.
Does it NOW work on the Inverter?
Does it NOW work on the generator?

Is it just the GFCI circuit or does the issue exist on other 120 VAC outlets. How about the microwave? Air Conditioner?

It may be a loose/intermittent connection just on that circuit.
It may be a bigger issue like an Automatic Transfer Switch issue.

You need to narrow the issue.

[NewToClassB]

Hello 16ACE27, You ask good questions. I will try to best answer your questions to narrow down the cause of the issue.




It NOW works on SP. - Yes

Does it NOW work on the Inverter? Have not tried it after plug into shore power. I will test it again with Inverter soon.


Does it NOW work on the generator? Have not tried it after plug into shore power. I will test it again with the generator soon.

Is it just the GFCI circuit or does the issue exist on other 120 VAC outlets. How about the microwave? Air Conditioner? It appears the issue exist with 2 GFCI circuit and one other 120 VAC outlet near the stove/sink area. Microwave and Air Conditioner works with generator on and shore power on.

[HarryS]

If that is the case, then you have a tripped/defective GFCI, or the breaker that controls the GFCI is tripped.

[16ACE27]

Originally Posted by HarryS

If that is the case, then you have a tripped/defective GFCI, or the breaker that controls the GFCI is tripped.

Then why would it only be a problem when NOT plugged into SP?

[16ACE27]

Originally Posted by NewToClassB

Hello 16ACE27, You ask good questions. I will try to best answer your questions to narrow down the cause of the issue.

Thanks. I've had 3 careers in my life; all involved troubleshooting. As an auto mechanic I learned how to best figure out the cause of problems. In the Navy they teach you a 7 step approach to logical troubleshooting: it was what I had already been doing but now they broke it down into steps and put a name on it.

Same approach applies to troubleshooting computers, RVs, and even medical issues.

[HarryS]

Originally Posted by 16ACE27

Then why would it only be a problem when NOT plugged into SP?

[Mo_Mike]

If something is working on SHORE POWER, but doesnt work on GENERATOR or INVERTER, there is an issue with a transfer switch somewhere. Not sure exactly how yours is wired, but would be time to track down a wiring diagram/schematic and see where the TRANSFER SWITCH is and how it is wired.

My TRANSFER SWITCH on my VEGAS had loose connections that actually arced and melted the wire nuts. Luckily found it and repaired before any real damage (except for trying to run the AIR COND on two out of three legs of electricity.

[madcpafl]

I have a 2021 Thor Tellaro 20AT and had the same problem. I found the cause of the problem was the circuit breaker on the GFIC outlet close to the floor and next to the bathroom was tripped. I reset the breaker and everything worked fine.

[bobhhoy]

The power has to go through two controllers or switches with a GFCI outlet. You have to have the GFCI outlet working at the plug, of course. Then the power to the GFCI also goes through the breaker switch panel. Check it to see if it has “tripped”.

[ThorRut]

Before going further, I would
- Pull off the GFI
- Hook up to SP
- Test the naked wires with Multimeter for 110v.
end

[bmennig]

I have a 2022 Thor Sequence 20K

All outlets work fine on either SP or Generator. GFCI tested and reset.

When on battery and turn on inverter there is no power to the GFCI and all outlets downstream (right side of van)

However, there is a pop-up power strip on the left side that work fine when on battery with inverter on.

All circuit breakers have been reset.

Scheduling to take it in but sure would like to know if it's something I should be able to fix.

[Beau388]

Originally Posted by bmennig

I have a 2022 Thor Sequence 20K

All outlets work fine on either SP or Generator. GFCI tested and reset.

When on battery and turn on inverter there is no power to the GFCI and all outlets downstream (right side of van)

However, there is a pop-up power strip on the left side that work fine when on battery with inverter on.

All circuit breakers have been reset.

Scheduling to take it in but sure would like to know if it's something I should be able to fix.

Generally with a small inverter (1000 watts or less) only a few specific 120 volts receptacles will be powered by the inverter. Usually the inverter powered receptacles are near the entertainment systems. Because of compatibility problems GFCI circuits are seldom powered by a square wave inverter.

[bmennig]

Thanks Beau388. That makes sense. You saved me a trip to the service center.

[LawrenceofPA]

I have a 2022 Tellaro 20L. According to the 120V distribution diagram, the inverter supplies designated outlets that are not GFCI.
I have verified that the inverter doesn't supply the outlets on the kitchen counter pop-up, and that it does supply the duplex outlet behind the passenger seat, where the fold-out table is.
I have not yet verified all of the non-GFCI outlets

[16ACE27]

Originally Posted by LawrenceofPA

I have a 2022 Tellaro 20L. According to the 120V distribution diagram, the inverter supplies designated outlets that are not GFCI.
I have verified that the inverter doesn't supply the outlets on the kitchen counter pop-up, and that it does supply the duplex outlet behind the passenger seat, where the fold-out table is.
I have not yet verified all of the non-GFCI outlets

OK.....

[Judge]

Originally Posted by LawrenceofPA

I have a 2022 Tellaro 20L. According to the 120V distribution diagram, the inverter supplies designated outlets that are not GFCI.
I have verified that the inverter doesn't supply the outlets on the kitchen counter pop-up, and that it does supply the duplex outlet behind the passenger seat, where the fold-out table is.
I have not yet verified all of the non-GFCI outlets

Go to the Thor Owners site and download the schematics for your coach. It will tell you exactly which outlets are on the Inverter circuit.


https://www.thormotorcoach.com/owners

[JeffsFreedomElite]

Problem: The generator will not power the Microwave and GFCI plugs. They all work using shore power.

Solution (from Thor Tech Support also Someone already posted this solution):
Check the circuit breaker on the generator. If tripped, the generator will run all day and not put out any power. Would have to go under coach to the generator, take the cover off and check the switch/breaker. If that doesn't work, it could be a transfer switch issue or something else.

Tellaro 20AT model year: 2022 built on a 2021 Promaster. I purchased it last week.