When using the A/C in very hot weather, the A/C 20 amp breaker gets hot (normal) and the main 30 amp breaker also gets hot. Since the A/C breaker is installed adjacent to the 30 amp breaker, I have experienced that the temperature is compounded and one or the other trips not because of current load but because of temperature. My solution has been to relocate the A/C breaker a couple of positions down so that it is not next to the 30 amp main. To make it easy I just swap breakers with the microwave. Again, this will prevent nuisance trips due to temperature not load.