CME NEC Code and Theory 3 — Questions and Answers
Question 1: Under NEC 250.66, the size of the grounding electrode conductor for a copper service entrance conductor sized at 2/0 AWG is determined by which table?
- Table 250.66 (Correct answer)
- Table 310.16
- Table 250.122
- Table 310.15(B)(16)
Correct answer: Table 250.66
NEC Table 250.66 is used to determine the minimum size of the grounding electrode conductor based on the largest service-entrance conductor.
Question 2: NEC 430.52 requires branch-circuit short-circuit and ground-fault protection for motors. For an inverse time circuit breaker protecting a Design B squirrel-cage motor, the maximum rating is what percentage of full-load current?
- 150%
- 175%
- 250% (Correct answer)
- 400%
Correct answer: 250%
NEC Table 430.52 allows inverse time circuit breakers for Design B squirrel-cage motors to be rated up to 250% of the motor's full-load current.
Question 3: According to NEC 358.20, what is the minimum trade size for Electrical Metallic Tubing (EMT)?
- 1/2 inch (Correct answer)
- 3/8 inch
- 3/4 inch
- 1/4 inch
Correct answer: 1/2 inch
NEC 358.20 specifies that the minimum trade size for EMT is 1/2 inch (metric designator 16).
Question 4: Which NEC article governs the installation of electrical systems in hazardous (classified) locations using the Zone equipment classification system?
- Article 501
- Article 505 (Correct answer)
- Article 511
- Article 516
Correct answer: Article 505
NEC Article 505 covers Class I, Zone 0, 1, and 2 hazardous locations using the Zone classification system.
Question 5: NEC 240.4(D) limits overcurrent protection for small conductors. What is the maximum OCPD permitted for 14 AWG copper conductors?
- 20 amperes
- 15 amperes (Correct answer)
- 25 amperes
- 30 amperes
Correct answer: 15 amperes
NEC 240.4(D)(3) limits overcurrent protection for 14 AWG copper conductors to a maximum of 15 amperes.
Question 6: Under NEC 410.116, luminaires installed in closets must maintain a minimum clearance of how many inches from the storage area when using recessed incandescent fixtures with a completely enclosed lamp?
- 12 inches (Correct answer)
- 6 inches
- 18 inches
- 24 inches
Correct answer: 12 inches
NEC 410.116(B) requires recessed incandescent fixtures with completely enclosed lamps to maintain at least 6 inches from the storage area, but surface-mounted incandescent fixtures need 12 inches — for recessed enclosed, the code permits 6 inches.
Question 7: Per NEC 680.22, what type of receptacles are required within 6 to 10 feet of the inside walls of a permanently installed swimming pool?
- Standard duplex receptacles
- GFCI-protected receptacles (Correct answer)
- Twist-lock receptacles only
- No receptacles are permitted in this zone
Correct answer: GFCI-protected receptacles
NEC 680.22(A)(1) requires all receptacles located between 6 and 10 feet of a permanently installed pool to be GFCI protected.
CME NEC Code and Theory 3
Under NEC 250.66, the size of the grounding electrode conductor for a copper service entrance conductor sized at 2/0 AWG is determined by which table?