NEC Overcurrent Protection & Controls 3 — Questions and Answers
Question 1: Where supplementary overcurrent protection is used, per NEC 240.10 it shall NOT be used as a substitute for what?
- Branch-circuit overcurrent protection (Correct answer)
- Surge protection
- Ground-fault protection of equipment
- Arc-fault protection
Correct answer: Branch-circuit overcurrent protection
NEC 240.10 states supplementary overcurrent protection is not a substitute for required branch-circuit overcurrent devices.
Question 2: Per NEC 240.24(A), overcurrent devices must generally be readily accessible and installed so the center of the operating handle is not more than what height above the floor?
- 1.8 m (6 ft)
- 2.0 m (6 ft 7 in.) (Correct answer)
- 2.5 m (8 ft)
- 3.0 m (10 ft)
Correct answer: 2.0 m (6 ft 7 in.)
NEC 240.24(A) limits the operating handle height to 2.0 m (6 ft 7 in.) above the floor or working platform.
Question 3: Per NEC 240.24(D), overcurrent devices shall not be located where exposed to what?
- Direct sunlight
- Physical damage (Correct answer)
- Cold temperatures
- Humidity below 30%
Correct answer: Physical damage
NEC 240.24(D) prohibits locating overcurrent devices where they would be exposed to physical damage.
Question 4: Per NEC 240.24(E), overcurrent devices shall not be located in what location in dwelling units?
- Bedroom closets
- Bathrooms (Correct answer)
- Hallways
- Basements
Correct answer: Bathrooms
NEC 240.24(E) prohibits overcurrent devices in bathrooms of dwelling units and guest rooms.
Question 5: Per NEC 240.24(F), overcurrent devices shall not be located over what?
- Steps of a stairway (Correct answer)
- A doorway
- A window
- An electric meter
Correct answer: Steps of a stairway
NEC 240.24(F) prohibits locating overcurrent devices over the steps of a stairway.
Question 6: Per NEC 240.32, enclosures for overcurrent devices in damp or wet locations shall comply with what requirement?
- Be painted with rust-inhibiting coating
- Prevent moisture or water from entering or accumulating (Correct answer)
- Be installed only indoors
- Use only plastic enclosures
Correct answer: Prevent moisture or water from entering or accumulating
NEC 240.32 requires damp/wet location enclosures to prevent moisture or water from entering and accumulating.
Question 7: Per NEC 240.33, enclosures for overcurrent devices shall generally be mounted in what position?
- Horizontal only
- In a vertical position unless that is impracticable (Correct answer)
- Face down
- At a 45-degree angle
Correct answer: In a vertical position unless that is impracticable
NEC 240.33 requires enclosures to be mounted vertically unless that orientation is shown to be impracticable.
NEC Overcurrent Protection & Controls 3
Where supplementary overcurrent protection is used, per NEC 240.10 it shall NOT be used as a substitute for what?