NEC Equipment for General Use Questions and Answers — Questions and Answers
Question 1: An electrician is installing general-use receptacles in a new dwelling unit's living room. According to NEC 210.52(A), what is the maximum distance that any point along the floor line of any wall space can be from a receptacle outlet?
- 12 feet
- 5.5 feet
- 6 feet (Correct answer)
- 10 feet
Correct answer: 6 feet
NEC 210.52(A)(1) requires that in dwelling units, receptacle outlets in habitable rooms be installed so that no point measured horizontally along the floor line in any wall space is more than 6 feet from a receptacle outlet. This rule ensures that an appliance with a standard 6-foot cord can be plugged in anywhere along the wall without needing an extension cord.
Question 2: Which of the following is a specifically prohibited use for flexible cords and cables according to NEC Article 400?
- For connection of portable lamps or appliances.
- As a substitute for the fixed wiring of a structure. (Correct answer)
- For the prevention of noise and vibration transmission.
- To facilitate the frequent interchange of utilization equipment.
Correct answer: As a substitute for the fixed wiring of a structure.
NEC 400.12(1) explicitly states that flexible cords and cables shall not be used as a substitute for the fixed wiring of a structure. The other options are all permitted uses under NEC 400.10.
Question 3: A permanently connected, 1/2 hp motor-operated appliance is installed in a commercial kitchen. The circuit breaker for this appliance is in a panelboard located in a separate room and is not within sight of the appliance. According to NEC 422.31(C), what is required?
- The appliance must be cord-and-plug-connected.
- The circuit breaker must be capable of being locked in the open position. (Correct answer)
- A second branch circuit must be run to the appliance.
- The appliance is not permitted in this configuration.
Correct answer: The circuit breaker must be capable of being locked in the open position.
NEC 422.31(C) requires that for a permanently connected motor-operated appliance rated over 1/8 hp, the disconnecting means shall be within sight from the appliance OR be capable of being locked in the open position. Since the circuit breaker is not within sight, it must be lockable.
Question 4: An electrician is installing a surface-mounted incandescent luminaire with a completely enclosed lamp in a clothes closet. What is the minimum clearance required between the luminaire and the nearest point of any closet storage space according to NEC 410.16(C)?
- 3 inches
- 6 inches
- 9 inches
- 12 inches (Correct answer)
Correct answer: 12 inches
NEC 410.16(C)(1) specifies a minimum clearance of 12 inches for surface-mounted incandescent or LED luminaires with a completely enclosed light source installed on the wall above the door or on the ceiling. This clearance is required to prevent the heat from the fixture from igniting combustible materials.
Question 5: According to NEC 404.12, metal enclosures for switches and circuit breakers must be connected to what?
- The grounded (neutral) conductor.
- The main service disconnect.
- An equipment grounding conductor. (Correct answer)
- A dedicated grounding electrode.
Correct answer: An equipment grounding conductor.
NEC 404.12 requires that metal enclosures for switches or circuit breakers be connected to an equipment grounding conductor. This creates an effective ground-fault current path to ensure that overcurrent devices will operate in the event of a fault to the enclosure.
Question 6: An industrial motor controller is located 100 feet away from the motor it controls and is not visible from the motor's location. According to NEC 430.102(B), which of the following is required for the motor's disconnecting means?
- A disconnecting means must be located in sight from the controller location only.
- A disconnecting means is not required for the motor itself, only the controller.
- A single, non-lockable disconnecting means can be used at the controller.
- A disconnecting means must be located in sight from the motor and driven machinery location. (Correct answer)
Correct answer: A disconnecting means must be located in sight from the motor and driven machinery location.
NEC 430.102(B)(1) requires a disconnecting means to be located in sight from the motor location and the driven machinery location. An exception exists in 430.102(B)(2) allowing the controller's disconnecting means to serve this purpose if it is lockable, but the general and primary rule is to have a disconnect within sight of the motor for safety during maintenance.
NEC Equipment for General Use Questions and Answers
An electrician is installing general-use receptacles in a new dwelling unit's living room.
According to NEC 210.52(A), what is the maximum distance that any point along the floor line of any wall space can be from a receptacle outlet?