NEC 2020 Code Questions Practice Test 1

Question 1: A 2/0 THWN conductor is placed in a dry location where the ambient temperature is 45⁰C. What is corrected ampacity of the conductor?

• 170 Amperes
• 160 Amperes
• 165 Amperes
• 175 Amperes

NEC Reference: NEC 310.15(B)(16)

Question 2: Which of the following locations Type AC cable cannot be used?

• Dry Location
• Wet Location
• Cable Trays
• Branch circuits for exposed work

Question 3: When a single generator is used to supply emergency load plus other loads, a single transfer switch can be sufficient to use.

• True
• False

NEC Reference: NEC 700.5(D)

Question 4: Mutli-wire branch circuits shall be permitted in class I division I locations.

• True
• False

NEC Reference: NEC 501.40

Question 5: Proper Grounding in electrical circuit limits ................. and protects the circuit.

• high voltage
• high current
• high power

Question 6: The branch circuits that are connected to luminaries of dwelling units shall have maximum voltage of ..................

• 120 volts
• 240 volts
• 208 volts
• 480 volts

NEC Reference: NEC 210.6

Question 7: The ampacity of the branch conductor that supplies a power supply to the motor which has FLC of 25 amperes is ...............

• 32 amperers
• 25 amperes
• 28 amperes
• 30 amperes

NEC Reference: NEC 430.22(A)

Question 8: Branch circuits and feeders to motor controllers, driving machines shall not exceed of…….. volts

• 600 volts
• 480 volts
• 240 volts
• 120 volts

NEC Reference: NEC 620.3(A)

Question 9: What is the maximum ampere rating of a power supply feeder of mobile homes?

• 25 amperes
• 50 amperes
• 75 amperes
• 45 amperes

NEC Reference: NEC 550.10

Question 10: Dispensing devices for liquefied petroleum gas shall be located not less than …………….. feet from any dispensing device for Class I liquids

• 5 feet
• 10 feet
• 8 feet
• 4 feet

NEC Reference: NEC 514.3(B)(2)

Question 11: 125 volt, 15 and 20 ampere receptacles that serve dwelling unit kitchen countertop surfaces require:

• No protection is required
• GFCI protection
• AFCI protection only
• A dedicated 50 ampere circuit

NEC Reference: NEC 210.8(A)(6)

Question 12: 125 volt, 15 and 20 ampere receptacles that serve dwelling unit kitchen countertop surfaces require:

• No protection is required
• GFCI protection
• AFCI protection only
• A dedicated 50 ampere circuit

NEC Reference: NEC 210.8(A)(6)

Question 13: AFCI protection is required for 120 volt, 15 and 20 ampere branch circuits supplying outlets in which areas of a dwelling unit?

• Bathrooms only
• Garages only
• Essentially all areas of the dwelling unit
• Only circuits over 20 amperes

NEC Reference: NEC 210.12(A)

Question 14: AFCI protection is required for 120 volt, 15 and 20 ampere branch circuits supplying outlets in which areas of a dwelling unit?

• Bathrooms only
• Garages only
• Essentially all areas of the dwelling unit
• Only circuits over 20 amperes

NEC Reference: NEC 210.12(A)

Question 15: For box fill calculations, a single switch or receptacle mounted on one strap counts as how many conductors?

• Zero
• One
• Two
• Three

NEC Reference: NEC 314.16(B)(4)

Question 16: For box fill calculations, a single switch or receptacle mounted on one strap counts as how many conductors?

• Zero
• One
• Two
• Three

NEC Reference: NEC 314.16(B)(4)

Question 17: Under NEC Table 110.26(A)(1), Condition 2 (exposed live parts on one side and grounded parts on the other) at 0-150 volts to ground requires a minimum working space depth of:

• 2 feet
• 3 feet
• 4 feet
• 5 feet

NEC Reference: NEC 110.26(A)(1)

Question 18: Under NEC Table 110.26(A)(1), Condition 2 (exposed live parts on one side and grounded parts on the other) at 0-150 volts to ground requires a minimum working space depth of:

• 2 feet
• 3 feet
• 4 feet
• 5 feet

NEC Reference: NEC 110.26(A)(1)

Question 19: A service is supplied by 2 AWG copper ungrounded conductors. What is the minimum size copper grounding electrode conductor required?

• 10 AWG
• 8 AWG
• 6 AWG
• 4 AWG

NEC Reference: NEC 250.66

Question 20: A service is supplied by 2 AWG copper ungrounded conductors. What is the minimum size copper grounding electrode conductor required?

• 10 AWG
• 8 AWG
• 6 AWG
• 4 AWG

NEC Reference: NEC 250.66

Question 21: A branch circuit is protected by a 60 ampere overcurrent device. What is the minimum size copper equipment grounding conductor required?

• 14 AWG
• 12 AWG
• 10 AWG
• 8 AWG

NEC Reference: NEC 250.122

Question 22: A branch circuit is protected by a 60 ampere overcurrent device. What is the minimum size copper equipment grounding conductor required?

• 14 AWG
• 12 AWG
• 10 AWG
• 8 AWG

NEC Reference: NEC 250.122

Question 23: In dwelling unit habitable rooms, receptacles must be placed so that no point along the floor line is more than how far from a receptacle outlet?

• 4 feet
• 6 feet
• 8 feet
• 10 feet

NEC Reference: NEC 210.52(A)(1)

Question 24: In dwelling unit habitable rooms, receptacles must be placed so that no point along the floor line is more than how far from a receptacle outlet?

• 4 feet
• 6 feet
• 8 feet
• 10 feet

NEC Reference: NEC 210.52(A)(1)

Question 25: Tamper-resistant receptacles are required in which areas of a dwelling unit?

• Only rooms where small children regularly stay
• Essentially all dwelling unit receptacles
• Only outdoor receptacles
• Only garage receptacles

NEC Reference: NEC 406.12

Question 26: Tamper-resistant receptacles are required in which areas of a dwelling unit?

• Only rooms where small children regularly stay
• Essentially all dwelling unit receptacles
• Only outdoor receptacles
• Only garage receptacles

NEC Reference: NEC 406.12

Question 27: A single raceway contains 4/0 AWG copper service-entrance conductors. What size copper supply-side bonding jumper is required?

• 4 AWG
• 2 AWG
• 1/0 AWG
• 3/0 AWG

NEC Reference: NEC 250.102(C)

Question 28: A single raceway contains 4/0 AWG copper service-entrance conductors. What size copper supply-side bonding jumper is required?

• 4 AWG
• 2 AWG
• 1/0 AWG
• 3/0 AWG

NEC Reference: NEC 250.102(C)

Question 29: A lighting and appliance branch-circuit panelboard must be protected by an overcurrent device with a rating not greater than the panelboard rating, except where the panelboard is rated:

• 200 amperes or more
• 400 amperes or more
• 100 amperes or more
• 600 amperes or more

NEC Reference: NEC 408.36

Question 30: A lighting and appliance branch-circuit panelboard must be protected by an overcurrent device with a rating not greater than the panelboard rating, except where the panelboard is rated:

• 200 amperes or more
• 400 amperes or more
• 100 amperes or more
• 600 amperes or more

NEC Reference: NEC 408.36

Question 31: Where a service mast is used for the support of service-drop conductors, it must be of adequate strength or supported by which method?

• It never needs additional support
• Adequate strength or braces/guy wires
• A separate structure must always be built
• It must be buried below grade

NEC Reference: NEC 230.28

Question 32: Where a service mast is used for the support of service-drop conductors, it must be of adequate strength or supported by which method?

• It never needs additional support
• Adequate strength or braces/guy wires
• A separate structure must always be built
• It must be buried below grade

NEC Reference: NEC 230.28

Question 33: Direct-buried service conductors not encased in concrete, under a residential driveway, generally require a minimum burial depth of:

• 6 inches
• 12 inches
• 24 inches
• 36 inches

NEC Reference: NEC 300.5

Question 34: Direct-buried service conductors not encased in concrete, under a residential driveway, generally require a minimum burial depth of:

• 6 inches
• 12 inches
• 24 inches
• 36 inches

NEC Reference: NEC 300.5

Question 35: A continuous-duty motor with a marked service factor of 1.15 or greater requires overload protection sized at not more than what percentage of the motor nameplate full-load current?

• 100 %
• 115 %
• 125 %
• 150 %

NEC Reference: NEC 430.32(A)(1)

Question 36: A continuous-duty motor with a marked service factor of 1.15 or greater requires overload protection sized at not more than what percentage of the motor nameplate full-load current?

• 100 %
• 115 %
• 125 %
• 150 %

NEC Reference: NEC 430.32(A)(1)

Question 37: Under the 25-foot transformer secondary conductor tap rule, the secondary conductors must terminate in a single overcurrent device rated no more than the conductor ampacity, and the conductors must be protected from physical damage. What is the maximum length permitted for these secondary conductors?

• 10 feet
• 15 feet
• 25 feet
• 50 feet

NEC Reference: NEC 240.21(C)(6)

Question 38: Under the 25-foot transformer secondary conductor tap rule, the secondary conductors must terminate in a single overcurrent device rated no more than the conductor ampacity, and the conductors must be protected from physical damage. What is the maximum length permitted for these secondary conductors?

• 10 feet
• 15 feet
• 25 feet
• 50 feet

NEC Reference: NEC 240.21(C)(6)

Question 39: What is the purpose of the equipotential bonding grid required around a permanently installed swimming pool?

• To reduce voltage gradients around the pool
• To increase the pool water pH
• To provide a path for lightning to ground only
• It has no safety function, only structural

NEC Reference: NEC 680.26(B)

Question 40: What is the purpose of the equipotential bonding grid required around a permanently installed swimming pool?

• To reduce voltage gradients around the pool
• To increase the pool water pH
• To provide a path for lightning to ground only
• It has no safety function, only structural

NEC Reference: NEC 680.26(B)

Question 41: Emergency power systems must be tested periodically to ensure the system is functioning correctly. Who is generally responsible for this periodic testing and maintenance?

NEC Reference: NEC 700.3

Question 42: Emergency power systems must be tested periodically to ensure the system is functioning correctly. Who is generally responsible for this periodic testing and maintenance?

• The premises owner
• The local fire department only
• The utility company
• No periodic testing is required

NEC Reference: NEC 700.3

Question 43: A 15 or 20 ampere, 125 or 250 volt receptacle installed outdoors in a wet location must be provided with an enclosure that is weatherproof:

• Only while no plug is inserted
• Whether or not a plug is inserted
• Only during rain
• A weatherproof cover is never required outdoors

NEC Reference: NEC 406.9(B)(1)

Question 44: When 4 or more conductors are installed in a single raceway, the maximum fill permitted is what percentage of the raceway cross-sectional area?

• 31 %
• 40 %
• 53 %
• 60 %

NEC Reference: NEC Chapter 9, Table 1

Question 45: A grounded (neutral) conductor 6 AWG or smaller must be identified by which color(s)?

• Black
• White or gray
• Red
• Green

NEC Reference: NEC 200.6(A)

Question 46: Flexible cords and cables are prohibited from being used as a substitute for which of the following?

• The fixed wiring of a structure
• Connecting a portable lamp
• Connecting a power tool
• Temporary holiday lighting

NEC Reference: NEC 400.12