Branch Circuits & FeedersPregunta 14 de 120
Nine current-carrying 10 AWG THHN copper conductors share one raceway at a 30 degrees C ambient. What is the adjusted ampacity of each?
a.35 amperes
b.24.5 amperes
c.26.3 amperes
d.28 amperes
Explicación
The 90 degrees C ampacity of 10 AWG copper is 40 A, and the adjustment factor for 7 through 9 current-carrying conductors is 70 percent: 40 x 0.70 = 28 A. The 26.3 A answer applies 70 percent to the 75 degrees C value, 24.5 A uses the 50 percent bracket that begins at 10 conductors, and 35 A ignores adjustment entirely.
Referencia Legal: 2023 NEC §310.15(C)(1)Practica las 120 preguntas gratis — sin registro.
Preguntas relacionadas de este tema
- What is the minimum branch-circuit rating for the receptacle outlets serving a dwelling unit bathroom?
- What is the allowable ampacity of 8 AWG copper Type NM cable?
- A feeder supplies a 100-ampere continuous load. Using 75 degrees C terminations and copper THWN, what is the minimum feeder conductor size?
- A four-wire, three-phase, 208Y/120-volt feeder supplies electric-discharge lighting, and the major portion of the load is nonlinear. How many current-carrying conductors are counted for adjustment purposes?
- Where must a multiwire branch circuit have a means to simultaneously disconnect all ungrounded conductors?
- In a dwelling unit living room, no point measured horizontally along the floor line of any wall space may be more than what distance from a receptacle outlet?
Última revisión: · proceso editorial
Equipo Editorial de PrepPass · Verificado con Journeyman Electrician Licensing Exam (NEC-based) · Cómo revisamos