Can I use a 60 A breaker with #6 romex? I'm confused by the allowable ampacity stated under 334.80 for NM. It states the allowable ampacity shall not exceed the 60 deg rating of 55 A but you can use the 90 deg C rating for ampacity adjustments as long as the adjustments don't exceed the 60 deg rating. My inverter has a 42 A output current so 42 x 1.25 = 52.5 A. So my breaker is 60 A. With a 55 A rating at 60 deg C the 60 deg wire rating is above 1.25 A x cont. current so the wire is able to handle the currents but am I allowed to use a 60 A breaker for this wire? Would the next size up rule in 240.4(B) allow me to use a 60 A breaker to protect the #6 romex? All my wiring is inside a wall so there are no correction/adjustment factors.
How is it the allowable ampacity can't exceed the 60 deg rating but you can use the 90 deg rating for adjustments?
How is it the allowable ampacity can't exceed the 60 deg rating but you can use the 90 deg rating for adjustments?