NEC Special Occupancies 5 — Questions and Answers
Question 1: Temporary electrical power for holiday decorative lighting is permitted for a maximum of how many days?
- 30 days
- 180 days
- 60 days
- 90 days (Correct answer)
Correct answer: 90 days
NEC 590.3(B) limits temporary holiday decorative lighting to 90 days.
Question 2: On a construction site, which receptacles that are not part of the permanent wiring must have GFCI protection for personnel?
- All 125-volt, single-phase, 15-, 20-, and 30-ampere receptacle outlets (Correct answer)
- Only 15-ampere receptacles
- Only receptacles outdoors
- Only receptacles within 6 feet of water
Correct answer: All 125-volt, single-phase, 15-, 20-, and 30-ampere receptacle outlets
NEC 590.6(A)(1) requires GFCI protection on all 125-V, single-phase, 15-, 20-, and 30-A temporary receptacle outlets.
Question 3: Where must the service equipment for a mobile home be located?
- Adjacent to the mobile home, not mounted in or on it, and within 30 feet of its exterior wall (Correct answer)
- At least 50 feet from the mobile home
- Inside the mobile home near the main entrance
- On the exterior wall of the mobile home
Correct answer: Adjacent to the mobile home, not mounted in or on it, and within 30 feet of its exterior wall
NEC 550.32(A) requires service equipment adjacent to, not on or in, the mobile home and within 30 ft of its exterior wall.
Question 4: When calculating the service load for a mobile home park, what is the minimum load per mobile home lot?
- 20,000 VA
- 16,000 VA (Correct answer)
- 10,000 VA
- 12,000 VA
Correct answer: 16,000 VA
NEC 550.31(1) sets a minimum of 16,000 VA per mobile home lot.
Question 5: At a marina, receptacles that provide shore power to boats must have ground-fault protection with a trip level not exceeding what?
- 300 mA
- 30 mA (Correct answer)
- 100 mA
- 5 mA
Correct answer: 30 mA
NEC 555.35(A)(1) limits ground-fault protection for shore power receptacles to 30 mA.
Question 6: In agricultural buildings, an equipotential plane is required in which location?
- Outdoor fenced pastures without electrical equipment
- Hay storage lofts
- Office areas within the barn
- Livestock confinement areas with concrete floors containing metallic equipment accessible to livestock (Correct answer)
Correct answer: Livestock confinement areas with concrete floors containing metallic equipment accessible to livestock
NEC 547.44 requires equipotential planes where livestock can contact metallic equipment on concrete floors.
Question 7: In a recreational vehicle park, what minimum percentage of sites with electrical supply must have a 50-ampere, 125/250-volt receptacle?
- 20% (Correct answer)
- 10%
- 5%
- 70%
Correct answer: 20%
NEC 551.71 requires at least 20% of RV sites with electrical supply to have a 50-A, 125/250-V receptacle.