Branch circuit Practice Questions

Question 1: The service disconnect for a mobile home should be located not less than ............ feet above platform

• 1
• 2
• 1/2
• 3

NEC Reference: NEC 550.32(F)

Question 2: What is the minimum tap conductor ampacity which supply 30 amperes industrial heating appliance?

• 10 amperes
• 15 amperes
• 20 amperes
• 25 amperes

NEC Reference: NEC 210.19(A)(4)

Question 3: An industrial heating appliance rated at 45 A is supplied by a tap conductor. what should be the minimum tap conductor ampacity?

• 10 amperes
• 15 amperes
• 20 amperes
• 30 amperes

NEC Reference: NEC 210.19(A)(4)

Question 4: A 2400 watts electric motor is connected to 240 volts single phase supply 2 wire circuit. What is the minimum size TW conductor that is required to carry the load?

• 14 AWG
• 12 AWG
• 10 AWG
• 8 AWG

NEC Reference: NEC 424.3(B)

Question 5: What should be the maximum percentage of cross sectional area of a conduit that should be occupied when three or more THW conductors are placed in a circuit.

• 40 %
• 50 %
• 30 %
• 70 %

Question 6: On a 25 ampere branch circuit what is the minimum size THW conductor that can be used?

• 14 AWG
• 8 AWG
• 12 AWG
• 10 AWG

NEC Reference: NEC 310.15(B)(16)

Question 7: If the branch circuit rating is more than ............. , the lamp holders connected to it should be of the heavy duty type.

• 20 amperes
• 25 amperes
• 40 amperes
• 45 amperes

NEC Reference: NEC 210.21(A)

Question 8: What is the maximum continuous load that can be connected to 240 volts 20 ampere branch circuit?

• 16 amperes
• 20 amperes
• 14 amperes
• 10 amperes

NEC Reference: NEC 210.20

Question 9: A 30 amperes branch circuit is permitted to supply fixed lightening units in ..................

• single family dwelling unit
• multi family dwelling unit
• Any occupancy
• Any occupancy other than dwelling unit

NEC Reference: NEC 210.23

Question 10: What will the  branch circuit calculated load for a single 12 KW electric range in a dwelling unit?

• 6 KW
• 8 KW
• 12 KW
• 15 KW

NEC Reference: NEC 220.55

Question 11: Which of the following is NOT a standard branch circuit rating recognized by the NEC?

• 20 amperes
• 30 amperes
• 35 amperes
• 50 amperes

NEC Reference: NEC 210.3

Question 12: A single piece of cord-and-plug connected equipment (not fastened in place) on a branch circuit that also supplies other loads shall not exceed what percentage of the branch circuit rating?

• 50%
• 80%
• 100%
• 125%

NEC Reference: NEC 210.23(A)(2)

Question 13: Per NEC 210.8, GFCI protection is required for 125 V, 15 and 20 A receptacles installed in which of the following dwelling unit locations?

• Bathrooms, kitchens, garages, and outdoors
• Only in the main bedroom closet
• Only in a formal dining room
• GFCI is never required in a dwelling unit

NEC Reference: NEC 210.8

Question 14: In a dwelling unit habitable room, no point measured horizontally along the floor line of any wall space should be more than ................. from a receptacle outlet.

• 3 feet
• 6 feet
• 10 feet
• 12 feet

NEC Reference: NEC 210.52(A)

Question 15: Along a dwelling unit kitchen countertop, no point measured horizontally along the countertop should be more than ................. from a receptacle outlet.

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

NEC Reference: NEC 210.52(C)

Question 16: How many 20 A small-appliance branch circuits does the NEC require, at minimum, for a dwelling unit kitchen?

• 1
• 2
• 3
• 4

NEC Reference: NEC 210.11(C)(1)

Question 17: The NEC requires a 125 V, 15 or 20 A receptacle outlet to be located within how many feet of HVAC equipment, for servicing purposes?

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

NEC Reference: NEC 210.63

Question 18: Per NEC 210.12, AFCI (Arc-Fault Circuit Interrupter) protection is required for most 120 V, 15 and 20 A branch circuits supplying outlets in which parts of a dwelling unit?

• Nearly all living areas, such as bedrooms, family rooms, and living rooms
• Only the attic
• Only unfinished basements
• AFCI is never required in dwellings

NEC Reference: NEC 210.12

Question 19: Under the general small-conductor overcurrent protection rule, what is the maximum standard overcurrent device rating permitted for a 14 AWG copper conductor?

• 15 amperes
• 20 amperes
• 25 amperes
• 30 amperes

NEC Reference: NEC 240.4(D)

Question 20: The Informational Note to NEC 210.19(A) recommends that branch circuit conductors be sized to keep voltage drop to no more than what percentage, for reasonable efficiency of operation?

• 1%
• 3%
• 10%
• 15%

NEC Reference: NEC 210.19(A)

Question 21: A multiwire branch circuit (two or more ungrounded conductors sharing a common neutral from the same panel) must be provided with a means to:

• Disconnect all ungrounded conductors simultaneously at the originating panel
• Disconnect only one ungrounded conductor at a time
• Never be disconnected once installed
• Share the same overcurrent device as an unrelated circuit

NEC Reference: NEC 210.4(B)

Question 22: On a 20 A branch circuit supplying two or more receptacles (other than individual circuits), which receptacle ampere ratings are permitted?

• 15 A or 20 A receptacles
• Only 30 A receptacles
• Only 10 A receptacles
• No receptacles are permitted on a 20 A circuit

NEC Reference: NEC 210.21(B)

Question 23: Per NEC 210.70(A)(1), a habitable room in a dwelling unit must have at least one lighting outlet that is:

• Controlled by a wall switch
• Controlled only by a pull chain out of reach
• Never required in any habitable room
• Required only in the kitchen

NEC Reference: NEC 210.70(A)(1)

Question 24: Under recent NEC editions, the branch circuit outlet supplying a dwelling unit dishwasher requires:

• GFCI protection
• No overcurrent protection at all
• AFCI protection only, never GFCI
• A dedicated 50 A circuit

NEC Reference: NEC 210.8(A)(7)

Question 25: A multiwire branch circuit sharing a common neutral must have all of its ungrounded conductors opened at the same time by a common disconnecting means.

• True
• False

NEC Reference: NEC 210.4(B)