We have encountered bad electrical supply pedestals at a couple of different RV parks in the past. Most recently, I kept trying to tell them that the circuit breaker needed to be replaced - but they insisted it was MY PROBLEM. They tested with a circuit tester and got a good reading, but that was without any type of load. Eventually we ran our power cord to the RV spot adjacent to ours and guess what...it worked flawlessly.
Finally - after 2 hours in the Texas heat and having to leave the motor and A/C running on the truck for the dogs and my wife - they conceded and changed out the circuit breaker. After that, we had zero problems. I don't know why they were so insistent that it was my problem and wasted so much time.