Licensed Electrical Contractor Licensed Electrical Contractor Special Occupancies and Equipment Questions and Answers 2 — Questions and Answers
Question 1: Per NEC Article 517, what is the maximum time permitted for the emergency system to restore power to life safety circuits in a hospital?
- 10 seconds (Correct answer)
- 30 seconds
- 60 seconds
- 120 seconds
Correct answer: 10 seconds
NEC 517.31 requires the emergency system to restore power to life safety branch circuits within 10 seconds of power interruption.
Question 2: Which NEC article governs the installation of electrical systems in hazardous (classified) locations involving flammable gases or vapors?
- Article 500 (Correct answer)
- Article 517
- Article 680
- Article 550
Correct answer: Article 500
NEC Article 500 covers the classification of hazardous locations where flammable gases, vapors, or combustible dusts may be present.
Question 3: When installing a swimming pool underwater luminaire operating at more than 15 volts, what is the minimum burial depth for a rigid metal conduit run from the forming shell to the junction box?
- 6 inches
- 12 inches
- 18 inches (Correct answer)
- 24 inches
Correct answer: 18 inches
NEC 680.23(F)(1) requires conduit runs from the forming shell to a deck box or junction box to be buried at least 18 inches below the deck surface.
Question 4: In a Class I, Division 1 hazardous location, which wiring method is generally required?
- Threaded rigid metal conduit with explosion-proof fittings (Correct answer)
- Type NM cable with weatherproof connectors
- Flexible metal conduit without seals
- EMT with compression fittings
Correct answer: Threaded rigid metal conduit with explosion-proof fittings
NEC 501.10(A) requires threaded rigid metal conduit or threaded steel intermediate metal conduit with explosion-proof fittings in Class I, Division 1 locations.
Question 5: What is the minimum required height for overhead service conductors crossing a commercial parking lot subject to truck traffic?
- 12 feet
- 15 feet
- 18 feet (Correct answer)
- 20 feet
Correct answer: 18 feet
NEC 225.18 requires overhead conductors to maintain at least 18 feet of clearance over areas subject to truck traffic.
Question 6: Per NEC Article 680, what is the minimum equipotential bonding grid wire size required for a permanently installed swimming pool?
- No. 12 AWG solid copper
- No. 10 AWG solid copper
- No. 8 AWG solid copper (Correct answer)
- No. 6 AWG solid copper
Correct answer: No. 8 AWG solid copper
NEC 680.26(C) requires the equipotential bonding grid conductor to be a minimum of 8 AWG solid copper.
Licensed Electrical Contractor Licensed Electrical Contractor Special Occupancies and Equipment Questions and Answers 2
Per NEC Article 517, what is the maximum time permitted for the emergency system to restore power to life safety circuits in a hospital?