Electrical

For those to fail is kind of rare, But as Dons said, breakers (And a few other things) do fail.. I would start there.. NOTE: Though one would THINK that the dual ganged 50 amp breaker in the park's box.. or in your motor home, is that way so that both sides (legs) trip together.. Such is not the case. that is often two standard single breakers with a tie bar between the handles but packaged in a single case.. (Sorry if that is hard to read)
One case with two breakers each independent, only the handles are tied together.