Thanks everybody. I should have mentioned that I specifically made sure he was installing a 30amp/ 120volt and not 220 volt before he started and it is a single slot. It is a dedicated circuit. I'm not sure how many amps the house has. It is a very small 1950s era house. The breaker in the garage trips as soon as it is plugged in. I also read that too many ground faults in the system can make it trip but the second electrician said that it still should not trip and could be a fire hazard. Could it just be that there are a lot of trailers out there that are fire hazards and no one knows because all the campground plugins are not grounded?