Breakers 167oF, art. 110.14 (C)(1)(a)

[medinajuli]

The NEC in article 110.14 (C)(1)(a) establishes the provisions for the equipment terminals of circuits with a nominal 100A or less: 1) use conductors with a nominal value of 60oC. Is it possible to use breakers designed to operate at 167 degrees Fahrenheit and thus be able to use rated conductors at the same temperature?. What line of breakers does this specify?. Thanks.

 

[kwired]

The NEC in article 110.14 (C)(1)(a) establishes the provisions for the equipment terminals of circuits with a nominal 100A or less: 1) use conductors with a nominal value of 60oC. Is it possible to use breakers designed to operate at 167 degrees Fahrenheit and thus be able to use rated conductors at the same temperature?. What line of breakers does this specify?. Thanks.

For the past 30 plus years nearly all circuit breakers (the common ones used in typical North American panelboards anyway) have had 75C (167F) rated terminals and yes you can use conductors at the ampacity in the 75C columns, provided the conductor itself has at least 75C insulation on it. Which most the commonly used conductors for past 30+ years also are 90C rated. Exceptions are NM and UF cable and in some cases SE cables which must use 60C ampacity table in all applications.