CEA NEC Code and Calculations 4

Question 1

Under NEC 230.79, what is the minimum ampacity of a service disconnect for a one-family dwelling?

Accepted Answer

100 amperes

Answer

NEC 230.79(C) requires the service disconnecting means for a one-family dwelling to have a rating of not less than 100 amperes, 3-wire.

Question 2

According to NEC 314.16, the minimum box fill for a 14 AWG conductor is how many cubic inches?

Accepted Answer

2 cubic inches

Answer

NEC Table 314.16(B) assigns a volume allowance of 2.0 cubic inches per 14 AWG conductor for box fill calculations.

Question 3

What NEC rule governs the use of extension cords in lieu of permanent wiring?

Accepted Answer

Extension cords must not be used as a substitute for permanent wiring

Answer

NEC 400.12 prohibits the use of flexible cords and cables, including extension cords, as a substitute for permanent wiring.

Question 4

A 240-volt, single-phase motor draws 18 amperes. What is the minimum branch circuit conductor ampacity required by the NEC?

Accepted Answer

22.5 amperes

Answer

NEC 430.22 requires motor branch circuit conductors to have an ampacity of at least 125% of the motor's full-load current: 18 × 1.25 = 22.5 amperes.

Question 5

Under the NEC, arc-fault circuit interrupter (AFCI) protection is required in which location of a dwelling unit?

Accepted Answer

All 120-volt, 15- and 20-ampere branch circuits in kitchens and living areas

Answer

NEC 210.12 has expanded AFCI requirements to cover all 120-volt, 15- and 20-ampere branch circuits throughout dwelling units including kitchens, family rooms, and living areas.

(CEA) Certified Electrical Apprentice Practice Test

(CEA) Certified Electrical Apprentice Practice Test

CEA NEC Code and Calculations 4