A hot connection could be several things, but the first that comes to mind is a loose connection somewhere. Did this only happen the last two time and was this at the same campground or different locations? Campground low voltage will also cause a higher current.....but, the 30A breaker "should" trip if the current gets over the rated capacity of the breaker. As far as connections go, those campground services get plugged into hundreds of times a year, and as a result, over time the recept. can get loose fitting. Did your plug feel like it went into the recept. with some effort or did it just kind of slide right in and not much resistance to plugging it in? That would/could be one source of a loose connection. Other sources could be anywhere along the line/cord and all the way to where the incoming power lands on the main breaker in your trailers power panel and breaker box.