Annoying Electrical Issue

It was a rainy day in southwest Louisiana today so I decided it was a good time to install that LED dimmer switch I bought a few weeks ago for the over the dining table candelabra light fixture. I keep my motorhome in an old metal shed with a roll up door on it at the family farm, there is power to the shed, but no working overhead lights, so I unplug the shore power cord, and proceed to swap out the plain rocker switch for the new one with a slider dimmer. I plug the motorhome back in and flip the switch, and get no light, I then go over to the kitchen 120V light switch, flip it, no light. Go back out to the breaker box flip the 50 amp breaker off and back on, no light, ....

As it turned out we had a power failure during the 5 minutes I was swapping out the switch.