tragusa3 wrote:
I just got back from picking up a receptacle tester. Plugged into the house and all outlets in the trailer were wired correctly.
Personally I would perform one more very simple and fast test. Grab the 30 amp plug from your trailer and pull, wiggle, and push on the ground pin. Make sure it's not loose in the end of the plug. I remember a post where somebody had a loose ground pin. It would usually make good contact because it was pushed in when plugging into the outlet. But if the cord was disturbed it would allow the pin to pull out slightly and break the ground.