CEA NEC Wiring and Protection 3 — Questions and Answers
Question 1: Per NEC 404.2(C), a grounded conductor (neutral) is required at switch locations for what purpose?
- To power the light fixture directly
- To supply power for electronic dimmer switches and timers (Correct answer)
- To serve as a ground fault path
- To bond the metal box
Correct answer: To supply power for electronic dimmer switches and timers
NEC 404.2(C) requires a grounded conductor at switch locations to provide a return path for electronic switches, dimmers, and occupancy sensors.
Question 2: What is the minimum burial depth for rigid nonmetallic conduit (PVC) under a residential driveway per NEC Table 300.5?
- 6 inches
- 12 inches (Correct answer)
- 18 inches
- 24 inches
Correct answer: 12 inches
NEC Table 300.5 requires PVC conduit to be buried at least 12 inches under a residential driveway.
Question 3: Which NEC section requires GFCI protection for receptacles in bathrooms of dwelling units?
- NEC 210.8(A)(1) (Correct answer)
- NEC 210.12(A)
- NEC 215.9
- NEC 230.95
Correct answer: NEC 210.8(A)(1)
NEC 210.8(A)(1) requires all 125-volt, 15- and 20-ampere receptacles in bathrooms of dwelling units to have GFCI protection.
Question 4: Under NEC 300.4(A), when bored holes in wooden studs for cables are less than 1-1/4 inches from the edge, what is required?
- A conduit sleeve
- A steel nail plate at least 1/16 inch thick (Correct answer)
- The cable must be in conduit
- No protection is needed if cable has armor
Correct answer: A steel nail plate at least 1/16 inch thick
NEC 300.4(A)(1) requires a steel plate at least 1/16 inch thick to protect cables bored through wood members where the edge clearance is less than 1-1/4 inches.
Question 5: How many current-carrying conductors trigger the first ampacity adjustment factor under NEC 310.15(C)(1)?
- More than 2
- More than 3 (Correct answer)
- More than 4
- More than 6
Correct answer: More than 3
NEC 310.15(C)(1) requires ampacity adjustment when more than 3 current-carrying conductors are bundled or installed in a raceway.
Question 6: Per NEC 250.122, the equipment grounding conductor size is based on:
- The load current
- The rating of the overcurrent protective device (Correct answer)
- The length of the circuit
- The wire gauge of the hot conductor
Correct answer: The rating of the overcurrent protective device
NEC 250.122 and Table 250.122 size the equipment grounding conductor based on the rating of the overcurrent device protecting the circuit.
Question 7: What NEC article covers armored cable (Type AC)?
- Article 320 (Correct answer)
- Article 330
- Article 334
- Article 338
Correct answer: Article 320
NEC Article 320 covers Armored Cable (Type AC), including permitted uses, installation requirements, and fittings.
CEA NEC Wiring and Protection 3
Per NEC 404.2(C), a grounded conductor (neutral) is required at switch locations for what purpose?