[jeff57]

Originally Posted by capnkirk4

Since we are now in year 3 with our Keystone Bullet on A/C (Dometic) number 3, is is possible that our 30amp power at the campsites have been responsible for frying the last 2 ACs? Dometic has been very gracious and stood behind them.

Yes it is very possible. We had A/C unit on a previous camper that fried about 5-6 years ago. All indicators are that it was a low-voltage scenario that took out our A/C (on a hot 4th of July weekend at a busy campground).
After some research I bought a 30A portable Progressive EMS for about $250 or so. If I would have had an EMS back then it would have shut off power to the camper. The EMS detects over/under voltage, no ground, no neutral, reverse polarity at the post and will prevent any of those situations from affecting your camper.
As MarkEHansen said "Don't leave home without it". It's cheap insurance compared to a new A/C unit, furnace, etc.
Hope this helps!