E2 Overcurrent Protection Devices

Question 1

Per NEC 240.4(D), what is the maximum overcurrent protection permitted for 14 AWG copper conductors in a commercial installation?

Accepted Answer

15 amperes

Answer

NEC 240.4(D) limits overcurrent protection for 14 AWG copper conductors to a maximum of 15 amperes to prevent conductor damage from overheating.

Question 2

According to NEC 240.4(D), what is the maximum overcurrent protection allowed for 12 AWG copper conductors?

Accepted Answer

20 amperes

Answer

NEC 240.4(D) specifies that 12 AWG copper conductors shall not be protected by overcurrent devices rated more than 20 amperes.

Question 3

Under NEC 240.4(D), what is the maximum overcurrent protection for 10 AWG copper conductors?

Accepted Answer

30 amperes

Answer

NEC 240.4(D) limits overcurrent protection for 10 AWG copper conductors to a maximum of 30 amperes.

Question 4

Which of the following is a standard ampere rating for overcurrent devices per NEC 240.6(A)?

Accepted Answer

45 amperes

Answer

NEC 240.6(A) lists 45 amperes as a standard overcurrent device rating; 55, 65, and 85 amperes do not appear in the standard rating sequence.

Question 5

Per NEC 240.21, overcurrent protection for conductors shall generally be provided at:

Accepted Answer

The point where the conductor receives its supply

Answer

NEC 240.21 requires overcurrent protection at the point where the conductor receives its supply from the feeder or service, protecting the entire conductor run.

(E2) E2 Commercial Electrical Inspector Practice Test

(E2) E2 Commercial Electrical Inspector Practice Test

E2 Overcurrent Protection Devices