Blown fuse

[Todger]

Talking to a fellow at the camp store today. He has a Montana 5th wheel that blows the 30 amp fuses. This can occur while hook to shore power of in transit. He had it back to his dealer and the factory with no results. Has anyone had a similar experience? My thought is a ground problem but not sure. If he only blows 1 fuse it is always the one to the heater.
That is all the info I have.