Licensed Electrical Contractor FREE Licensed Electrical Contractor Special Occupancies and Equipment Questions and Answers 2 — Questions and Answers
Question 1: What is the maximum voltage permitted for fixed electric space-heating equipment installed in a hazardous (classified) location per NEC Article 500?
- 600 volts
- 1000 volts
- Equipment is prohibited in hazardous locations
- Voltage depends on the class and division (Correct answer)
Correct answer: Voltage depends on the class and division
The NEC permits electric heating equipment in hazardous locations, but the allowable voltage and installation requirements depend on the specific class, division, and group classification.
Question 2: Per NEC Article 517, what is the maximum time permitted for the life safety branch of an essential electrical system in a healthcare facility to restore power after a utility outage?
- 30 seconds
- 10 seconds (Correct answer)
- 60 seconds
- 15 seconds
Correct answer: 10 seconds
NEC Article 517.31 requires the life safety branch to have power restored automatically within 10 seconds of utility power interruption.
Question 3: When installing wiring in a commercial garage classified as a Class I, Division 2 location, which wiring method is NOT permitted?
- Rigid metal conduit
- Type MC cable with gas-tight jacket
- Standard NM cable (Correct answer)
- Intermediate metal conduit
Correct answer: Standard NM cable
Standard NM (nonmetallic-sheathed) cable is not permitted in Class I, Division 2 locations; approved methods include rigid metal conduit, IMC, and listed MC cable with gas-tight fittings.
Question 4: What grounding requirement applies to patient care vicinity receptacles in a healthcare facility per NEC Article 517?
- Standard equipment grounding conductor only
- Redundant grounding path using two equipment grounding conductors (Correct answer)
- Isolated ground only
- No grounding is required if GFCI protected
Correct answer: Redundant grounding path using two equipment grounding conductors
NEC 517.13 requires redundant grounding in patient care areas, mandating both a metallic raceway or cable armor and an insulated copper equipment grounding conductor.
Question 5: In a swimming pool area, what is the minimum distance an overhead service conductor must maintain from the pool edge per NEC Article 680?
- 10 feet horizontally
- 22.5 feet horizontally (Correct answer)
- 15 feet horizontally
- No overhead conductors are permitted near pools
Correct answer: 22.5 feet horizontally
NEC 680.8 requires that overhead service conductors maintain a minimum horizontal distance of 22.5 feet from the inside wall of a pool.
Question 6: What type of ground-fault protection is required for a 15-ampere, 125-volt receptacle installed outdoors at a commercial occupancy per NEC Article 210?
- AFCI protection
- GFCI protection (Correct answer)
- Both GFCI and AFCI protection
- No special protection required
Correct answer: GFCI protection
NEC 210.8(B) requires GFCI protection for 15- and 20-ampere, 125-volt receptacles installed outdoors at commercial occupancies.
Licensed Electrical Contractor FREE Licensed Electrical Contractor Special Occupancies and Equipment Questions and Answers 2
What is the maximum voltage permitted for fixed electric space-heating equipment installed in a hazardous (classified) location per NEC Article 500?