Wiring Methods and Materials Flashcards
7 cards from real Licensed Electrical Contractor practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Wiring Methods and Materials flashcards as text
When using liquidtight flexible nonmetallic conduit (LFNC), what is the maximum length permitted for a single run used as a fixed raceway?
Answer: 6 feet
NEC 356.60 limits LFNC used as a fixed raceway to 6 feet in length except where used for lighting fixtures or where flexibility is necessary.
Which insulation type is rated for use in both wet and dry locations at 75°C?
Answer: THW
Type THW is rated 75°C in both wet and dry locations, making it suitable for outdoor or damp environment wiring.
Intermediate metal conduit (IMC) has a wall thickness that is:
Answer: Thinner than RMC but thicker than EMT
IMC has a wall thickness between the heavy-wall RMC and the thin-wall EMT, offering a balance of strength and weight savings.
What is the maximum ambient temperature rating for Type THHN conductors?
Answer: 90°C
Type THHN conductors are rated for 90°C in dry locations, though ampacity is typically derated to 75°C at terminations per NEC 110.14(C).
When Type NM cable passes through a metal framing member, which protection is required?
Answer: A steel nail plate at least 1/16 inch thick
NEC 300.4(B)(1) requires a steel nail plate at least 1/16-inch thick to protect NM cable passing through metal framing members less than 1-1/4 inches from the edge.
Polyvinyl chloride (PVC) conduit Schedule 40 is NOT permitted to be used:
Answer: As an equipment grounding conductor path alone
PVC conduit is non-metallic and cannot serve as an equipment grounding path; a separate EGC must be installed inside per NEC 352.60.
What is the minimum size rigid metal conduit permitted for use as a raceway?
Answer: 1/2 inch trade size
NEC 344.20 establishes 1/2-inch trade size as the minimum size for rigid metal conduit used as a wiring method.