On a recent trip, strange things started happening to the 120volt circuits. The converter would go on and off and a 120v lamp that I installed would do the same. The microwave display would flicker.
I laid my hand on the breaker box and found that it was almost too hot to touch. Poking around inside, I drew sparks from two of the white wires at the ground buss bar. Looking closer, I found that the insulation had burned and melted back for about an inch on these two white wires.
I found that I could tighten the screws for these wires almost a full turn. That solved one circuit, but the second circuit (microwave) would still spark a bit. We didn't use the microwave for the last two days of the trip.
After arriving home, I cut off the ends of these wires, stripped them, reinserted them, and firmly tightened all connections. The breaker box stays cool now.
What is interesting is that these wires had not been touched in all the time and miles since the trailer was built in 1955
. It may pay for folks to check the tightness of wires in the breaker box using the obvious precaution of unplugging the trailer from outside AC power.