We have been at Casa Grande RV Park in hot hot AZ and the same thing happened repeatedly 3 days ago while the temp was 112 degrees. (We are usually not there during daylight hours.) However, at first we did have both the washer, dryer, tv, and some lights on at the same time. Turn off the dryer and lights and still tripped, but took a little longer to do so. Turned of the washer and tv and no more tripping. After reading Jim's idea I suspect that we have both ACs on the same hot leg.