IEC Special Occupancies and Equipment 2 — Questions and Answers
Question 1: In a Class I, Division 1 hazardous location, which wiring method is acceptable?
- Type NM cable
- Rigid metal conduit (RMC) (Correct answer)
- Type AC cable
- Open wiring on insulators
Correct answer: Rigid metal conduit (RMC)
Rigid metal conduit is approved for Class I, Division 1 locations because it provides the required explosion-proof enclosure integrity.
Question 2: What NEC article governs electrical installations in health care facilities?
- Article 500
- Article 517 (Correct answer)
- Article 520
- Article 547
Correct answer: Article 517
NEC Article 517 specifically covers health care facilities including hospitals, nursing homes, and limited care facilities.
Question 3: A swimming pool light fixture installed below the normal water level must be listed for use at what voltage or less?
- 12 volts
- 15 volts (Correct answer)
- 120 volts
- 150 volts
Correct answer: 15 volts
NEC 680.23 requires luminaires installed facing upward within the pool to operate at 15 volts or less.
Question 4: Which of the following areas in a commercial garage is classified as a Class I, Division 2 hazardous location?
- Office area above the garage
- Area up to 18 inches above the floor (Correct answer)
- Outdoor parking lot surface
- Ventilated storage room above grade
Correct answer: Area up to 18 inches above the floor
In commercial garages, the area from floor level to 18 inches above the floor is classified Class I, Division 2 due to heavier-than-air gasoline vapors.
Question 5: Mobile homes must have a minimum electrical service of at least how many amperes?
- 60 amperes
- 100 amperes (Correct answer)
- 150 amperes
- 200 amperes
Correct answer: 100 amperes
NEC 550.11 requires mobile homes to have a minimum 100-ampere, 120/240-volt service.
Question 6: In a theater, what is the required clearance above the stage floor for equipment operating over 150 volts to ground?
- 7 feet
- 8 feet (Correct answer)
- 10 feet
- 12 feet
Correct answer: 8 feet
NEC Article 520 requires a minimum 8-foot clearance above the stage floor for exposed live parts over 150 volts in theaters.
Question 7: For a carwash facility, all 125-volt, single-phase, 15- and 20-ampere receptacles must be protected by:
- AFCI breakers
- GFCI protection (Correct answer)
- Double-pole breakers
- Tamper-resistant covers only
Correct answer: GFCI protection
Carwash facilities are wet locations requiring GFCI protection on all 125-volt, 15- and 20-ampere receptacles per NEC 422.5.
IEC Special Occupancies and Equipment 2
In a Class I, Division 1 hazardous location, which wiring method is acceptable?