dougrainer wrote:
For ScottG. I looked up the breaker info at work from the NEC. Doug
Circuit Breaker Ampere Ratings
Circuit breakers have an ampere rating (typically marked on the end of the operating handle). This is the maximum continuous current that the breaker can carry without exceeding its rating. As a general rule the circuit breaker’s ampere rating should be the same as the conductor’s ampacity.
Circuit breakers are designed to handle their rated current indefinitely at an ambient temperature of 104 degrees in open surroundings if manufactured to meet UL standard 489. Breakers are seldom mounted in open air. Mount it in a breaker panel with a cover, surrounded by other breakers generating heat and everything changes. Hence the NEC 80% load rating for continuous loads. Now an RV is not considered a continuous load. It's expected that A/C compressors, fridges, water heaters will cycle on and off. Certainly in hot weather 2 A/C compressors may run continuously for more than 3 hours. Does that mean the breaker will pop, maybe, maybe not. You have to account for the other factors. Temp, other breakers in the panel and what their load factor is and the type of enclosure.
So you can't make a blanket statement that a breaker can only be loaded to 80% of it's rated capacity because it's just not true. If you run at full capacity and exceed the '3 hour continuous load' does that mean the breaker will trip? Again, maybe, maybe not.
