Journeyman Electrician’s Exam Wiring Methods and Materials 2 — Questions and Answers
Question 1: What distinguishes Type AC cable from Type MC cable regarding the equipment ground?
- AC uses aluminum conductors throughout
- AC contains an internal bonding strip and relies on the armor for grounding (Correct answer)
- MC requires conduit protection in all locations
- AC has a PVC outer jacket
Correct answer: AC contains an internal bonding strip and relies on the armor for grounding
Type AC cable uses an internal aluminum bonding strip working with the armor as the equipment ground, while Type MC cable contains a dedicated EGC wire.
Question 2: Type UF cable is specifically designed and listed for which primary application?
- Indoor dry locations only
- Direct burial underground (Correct answer)
- Wet locations above grade in conduit
- Exposed outdoor runs on structures
Correct answer: Direct burial underground
Type UF (Underground Feeder) cable is listed for direct burial and is rated for continuous exposure to moisture underground.
Question 3: Per NEC Table 310.16, what is the ampacity of a 12 AWG copper conductor with 90°C (THHN) insulation in a raceway?
- 20 amperes
- 25 amperes (Correct answer)
- 30 amperes
- 15 amperes
Correct answer: 25 amperes
NEC Table 310.16 lists 12 AWG copper in the 90°C column at 25 amperes, though termination limits often restrict use to 20A.
Question 4: When flexible metal conduit (FMC) exceeds 6 feet in length, what additional grounding measure is required?
- No additional measure needed
- A separate equipment grounding conductor inside the FMC (Correct answer)
- A bonding bushing at the panel only
- Grounding is prohibited through FMC
Correct answer: A separate equipment grounding conductor inside the FMC
Per NEC 350.60, FMC longer than 6 feet cannot serve as the sole equipment ground; a separate EGC must be installed inside.
Question 5: Per NEC 330.30, at what maximum interval must Type MC cable be supported when installed on structural members?
- 3 feet
- 4.5 feet
- 6 feet (Correct answer)
- 10 feet
Correct answer: 6 feet
NEC 330.30 requires Type MC cable to be supported and secured at intervals not exceeding 6 feet.
Question 6: Which wiring method is permitted in a Class I, Division 1 hazardous (classified) location?
- EMT with set-screw fittings
- Type NM cable
- Rigid metal conduit (RMC) with threaded fittings (Correct answer)
- Type AC cable
Correct answer: Rigid metal conduit (RMC) with threaded fittings
RMC with threaded, explosionproof fittings is one of the wiring methods permitted in Class I, Division 1 locations per NEC 501.10(A).
Journeyman Electrician’s Exam Wiring Methods and Materials 2
What distinguishes Type AC cable from Type MC cable regarding the equipment ground?