Question Vbus over range fault 18kpv

@wfbiggin If it turns out that it is just the living room circuit, I suggest you first check your outlets with an outlet tester, a decent one is not very expensive and it will tell you if you have a polarity fault or a ground fault.  For the lights on the circuit, if they are traditional 120v screw in bulbs then you can grab a screw in outlet and use the aforementioned tester.  They will most likely show a ground fault but at least it is some information.  If they are just 12VDC lights, then the best bet is to just do a very good visual inspect for indications of historical sparks. Or if you can completely shut down the RV's DC and AC you can test the light fixture with a meter.  Keep in mind, if it turns out to be an issue with the living room circuit, it could be any of the following:

The fixtures

The outlets

The wiring from the breaker to any of the above

Or the breaker itself.

Although most of this is tedious to test, it is all testable.

JB

@wfbiggin 

I expect all the lights in the RV are 12VDC so none of them should be on that living room branch circuit. Are there actually some lights not working when only that one living room AC breaker is off?

FYI, in general the entire 12VDC system in the RV will be isolated from the VAC side of things, via a single 120VAC circuit breaker labeled "converter" as I mentioned earlier. But if there are any 12VDC things not working in the RV, that may be a clue so don't ignore it.

The AC and DC systems will likely share a common ground in power distribution center - look for a ground bus inside that panel or possibly just outside the box. And also, the 12VDC negative will be tied to frame ground which means your AC power is also grounded to the RV frame. This is one reason you can have weird things happening with RV wiring - if there's an NG bond somewhere, and then also a neutral path fault somewhere, this can result in a hot skin condition where the entire RV frame is energized and providing the neutral return path for the VAC.

I mention the common ground and hot skin problem because, relevant to your problem on the living room circuit, if some of those outlets are in a slide-out module on the camper then the moving wires in the slide-out are at risk of becoming abraded and possibly shorted to the metal slide-out frame. There might then be some kind of a short in the living room circuit that isn't tripping a breaker but is creating a ground fault at the inverter.