Problem with shore power

[imolared]

Howdy,
Prepping for trip, leaving Friday AM.
Montana 3120RL 2019
Minutes ago the ref switched to gas after running on AC all day.
The ref, micro and TV are not running.
starting the generator, then all three above run.
The ref fuse works.
I reset all circuit breakers.
The only GFI I can find is in the bathroom. It is just like the ref-micro-TV meaning that outlet only works when the gen is on.
Looking for ideas.
thanks,
-ed

[BB_TX]

Sounds like your transfer switch. Been a lot of discussion about problems with those.

[imolared]

Actually I attempted to edit my post
It appears that the shore power goes through the surge protector but des not get to the RV

I do not know where to look for fuse/breaker

thanks,
-ed

[AZ Traveler]

Ed,

Are you hooked into a 50 amp circuit? Is your ems/surge protector internal or external? A little more info would be helpful. I assume you have checked for voltage at your internal circuit breakers with a voltmeter.

A potential issue is your cable going into the rig.

[BB_TX]

Does anything at all in the trailer work on 120 vac when on shore power?

Except for the park pedestal breaker there should not be any breaker unique to the shore power. Assuming you have an automatic power transfer switch, that transfer switch has shore power to one set of contacts and generator power to a second set of contacts. Form “C” contacts; NO/NC/COM. Depending on what power is available, the switch will connect AC power from one source or the other to a common path to your AC breaker panel.

Is your surge protector before your transfer switch? If shore power is getting thru your surge protector to the transfer switch, but not to the breaker panel, then shore power is apparently not getting thru the transfer switch. But starting the generator does supply power thru the transfer switch. That is the common problem I mentioned earlier. The transfer switch is not closing the contacts properly for shore power but is for generator power.

I don’t have a transfer switch and so am not familiar with those particular ones used on a Montana. But if you can access the wire connections, and are comfortable troubleshooting live 120/240 vac, then you can quickly determine if that is your problem.