Equipment for General Use (NEC 400/402/408/424/440/480) — NEC 2023 Edition

Question 1: Which of the following is the minimum approved wire size that is permitted for a device which is permanently attached to the building?

• 12 AWG
• 16 AWG
• 18 AWG
• 10 AWG

NEC Reference: NEC 402.6

Question 2: The dust breaker shall not be installed on .........................

• Panel Boards
• Junction boxes
• Enclosures
• Boxes

NEC Reference: NEC 408.36(C)

Question 3: If a 20 amp branch circuit supplies only 120 volt cord and plug type window air conditioner cannot have full load rating of which of the following?

• 10 amp
• 16 amp
• 18 amp
• 20 amp

NEC Reference: NEC 440.62(B)

Question 4: A Transformer vault doorway that is protected with automatic sprinkler, water spray shall have a minimum fire rating of ......................

• 1 hour
• 3 hours
• 1/2 hour
• 2 hours

Question 5: Even if the Ground Fault interrupter protection is provided for impedance heating elements, What is the maximum transformer secondary voltage permitted?

• 30 volts
• 80 volts
• 65 volts
• 50 volts

Question 6: Fixed outdoor electric deicing and snow melting equipment shall be considered as ..................

• continuous load
• Non continuous load
• Heavy load
• Not important load for service conductor calculations

Question 7: Which of the following is an allowable ampacity of an 10 AWG fixture wire?

• 23 amp
• 17 amp
• 28 amp
• 30 amp

NEC Reference: NEC 402.5

Question 8: Which of the following is the nominal voltage of lead-acid cell?

• 2 volts
• 1.2 volts
• 1.7 volts
• 2.2 volts

NEC Reference: NEC 480.2

Question 9: Which of the following is a 300 volts motor disconnecting means?

• At Least 125% of motor full load current
• Not less than 115% of motor full load current
• Not Greater Than 120% motor full load current
• 150 amperes

Question 10: Which of the following is not a rating of a branch circuit used for electric space heaters installed in dwelling family unit?

• 30 amp
• 40 amp
• 20 amp
• 25 amp

NEC Reference: NEC 424.3

Question 11: A flexible cord generally cannot be used as a substitute for what?

• The fixed wiring of a structure
• A portable lamp cord
• An extension cord
• A tool cord

NEC Reference: NEC 400.12

Question 12: Per NEC 408.36(C), dust-tight circuit breakers are restricted from being installed in which equipment?

• Panelboards
• Motor control centers
• Switchgear
• Meter sockets

NEC Reference: NEC 408.36(C)

Question 13: A single cord-and-plug window air conditioner is supplied by a 15-ampere branch circuit. What is the maximum full-load current rating permitted for that unit?

• 12 amperes
• 15 amperes
• 10 amperes
• 18 amperes

NEC Reference: NEC 440.62(B)

Question 14: If a transformer vault doorway is NOT protected by an automatic sprinkler or water spray system, what fire rating does it generally require, versus the 1-hour rating used when sprinklers ARE present?

• A higher rating (typically 3 hours)
• The same 1-hour rating
• No fire rating is ever required
• Exactly half an hour

NEC Reference: NEC 450.43

Question 15: Without ground-fault protection, impedance heating systems generally have a lower maximum transformer secondary voltage limit than the 80-volt limit that applies when GFCI protection IS provided. True or false?

• True
• False
• Voltage limits do not depend on GFCI protection
• GFCI protection is never used with impedance heating

NEC Reference: NEC 426/427 (impedance heating)

Question 16: What is the general definition of a "continuous load" under the NEC?

• Maximum current expected to continue for 3 hours or more
• Any load running for more than 10 minutes
• Any load over 50 amperes
• Only loads running 24 hours a day

NEC Reference: NEC Article 100

Question 17: What is the allowable ampacity of a 14 AWG fixture wire, per NEC Table 402.5?

• 35 amperes
• 25 amperes
• 30 amperes
• 40 amperes

NEC Reference: NEC Table 402.5

Question 18: What is the nominal voltage of an alkali (nickel-cadmium type) cell, per NEC 480.2?

• 1.2 volts
• 2 volts
• 3.6 volts
• 1.5 volts

NEC Reference: NEC 480.2

Question 19: A 300-volt motor has a full-load current of 40 amperes. What is the minimum ampere rating generally required for its disconnecting means?

• 46 amperes
• 40 amperes
• 50 amperes
• 60 amperes

NEC Reference: NEC 430.110

Question 20: Branch circuits for fixed electric space-heating equipment in a dwelling unit are generally rated at which of the following?

• 15, 20, 25, or 30 amperes
• 15, 20, 30, or 40 amperes
• 20, 30, 40, or 50 amperes
• Any rating is permitted with no limit

NEC Reference: NEC 424.3

Question 21: Per the NEC informational note in 480.2, what is roughly the nominal voltage of a lithium-ion (Li-ion) cell?

• About 3.6-3.8 volts
• 2 volts
• 1.2 volts
• 12 volts

NEC Reference: NEC 480.2

Question 22: Equipment intended for use in dusty locations is generally listed and marked for what type of service?

• "Dust-tight" or for the classified location
• No marking is ever required
• Only a serial number
• Only a UL sticker with no wording

NEC Reference: NEC 100 / 500 series

Question 23: When MORE than one cord-and-plug room air conditioner is supplied by the same branch circuit, what total percentage of the branch-circuit rating applies, per NEC 440.62?

• Up to 100%, under 440.62(A) conditions
• Always exactly 80%, same as a single unit
• Always exactly 50%
• This is never permitted

NEC Reference: NEC 440.62(A)

Question 24: Because fixed outdoor deicing and snow-melting equipment is treated as a continuous load, its branch-circuit conductors and overcurrent protection are generally sized at not less than what percentage of the load current?

• 125%
• 100%
• 80%
• 150%

NEC Reference: NEC 426.4

Question 25: The allowable ampacity of a fixture wire, listed in NEC Table 402.5, depends primarily on its conductor size and what other characteristic?

• The insulation temperature rating
• The wire's color
• The manufacturer only
• Nothing else matters

NEC Reference: NEC Table 402.5

Question 26: True or false: panelboards must generally be of dead-front construction, meaning no live parts are exposed on the front.

• True
• False
• Only for panelboards over 400A
• Only in dwelling units

NEC Reference: NEC 408.38

Question 27: Fixed outdoor deicing and snow-melting equipment installed in wet areas generally requires what type of personnel protection, per NEC 426?

• Ground-fault protection of equipment (GFPE)
• No protection is required
• Only a fuse, no GFCI/GFPE
• Only a disconnect switch

NEC Reference: NEC 426.28

Question 28: Storage battery installations that can produce hydrogen gas generally require what, per NEC Article 480?

• Ventilation to prevent hydrogen gas accumulation
• No special provisions are ever needed
• A fire sprinkler only
• A dedicated 20A receptacle only

NEC Reference: NEC Article 480

Question 29: What is the general purpose of a fire-rated door on a transformer vault, per NEC 450.43?

• To contain fire and limit its spread
• To keep out sunlight
• To reduce noise only
• It has no fire-related purpose

NEC Reference: NEC 450.43

Question 30: Fixed electric space-heating cable sets and heating panels are generally required to be marked with what information?

• Rating in volts and watts (or volts and amperes)
• No marking is ever required
• Only the installer's name
• Only the installation date

NEC Reference: NEC 424.35