We're just ending a week at Lake Havasu City, AZ. Temperatures reached a 100 degrees and we started using our air conditioner. Before this we've never had any problem. Well it started tripping the 50 amp breaker. We checked the loads and turned off fans etc. Seemed to help but the next day it did it again and this time I smelled an oder around the breaker panel. Investigation revieled that the screw on the breaker holding the wire was not tight. I actually found some carbon on the wire. So what was happening, the loose connection caused heat to build up and this resulted in the breaker tripping. I tightened the screw and the AC has been running all day today again over 100 degrees.