NEC Overcurrent Protection & Grounding 3

Question 1

Which NEC section requires Arc-Fault Circuit-Interrupter (AFCI) protection for bedroom branch circuits in dwelling units?

Accepted Answer

210.12

Answer

NEC 210.12 mandates AFCI protection for branch circuits supplying outlets in dwelling unit bedrooms and other specified areas.

Question 2

Under NEC 250.52, which of the following is a permitted grounding electrode?

Accepted Answer

A concrete-encased electrode (Ufer ground)

Answer

NEC 250.52(A)(3) recognizes concrete-encased electrodes (Ufer grounds) as a permitted grounding electrode type.

Question 3

What is the maximum rating of a fuse or inverse-time circuit breaker that may be used to protect a 10 AWG copper conductor (ampacity 30A) under NEC 240.4(B)?

Accepted Answer

30 amperes

Answer

Under 240.4(B), the next standard size above conductor ampacity is permitted, but 30A is the exact ampacity so 30A is used directly.

Question 4

Per NEC 250.66, the size of the grounding electrode conductor (GEC) for a service is based on:

Accepted Answer

The size of the largest service-entrance conductor

Answer

NEC Table 250.66 sizes the GEC based on the largest service-entrance conductor or equivalent area for parallel conductors.

Question 5

Which statement about double-pole (2-pole) circuit breakers is correct per NEC requirements?

Accepted Answer

They must simultaneously disconnect both ungrounded conductors

Answer

NEC 240.20(B) requires multipole breakers to simultaneously open all ungrounded conductors of the circuit.

NEC Practice Test

NEC Practice Test

NEC Overcurrent Protection & Grounding 3