If I understand what you are saying, you have an RV with a 50 amp service. Yes? It's really two 50 amp 120 volt circuits in the pigtail which you reduce to one 30 amp at the pedestal. (house plug) The main circuit breaker(s) in your RV aren't going to flip until they reach 50 amps. (only one is being used) The house circuit breaker will flip at 30 amps. So, now you have a 50 amp potential draw fed by a 30 amp breaker. Add in a few extension cords, a few bad connections, and you WILL shortly find the weakest link, which you did.
Chum lee