Message: I studied NEC2008, did a load analysis got a building permit and had inspector come when I put in a 240v, 30a electric vehicle charging station last year. I've had the breaker trip when I had a lot of load on it but not over 70 amps worth. ( house A/C, clothes dryer, electric car charger) I thought the 100a main was just old and changed it, but still having a problem with the new breaker tripping. When I go to the breaker box I find the upper half of the 100a main breaker and the 40a charger breaker about 20F hotter than the lower half. (used a digital thermometer gun 158F upper 135F lower) So does that mean maybe a connection on one phase is not tight?