NEC 2020 Code Questions Practice Test 7

Question 1: What is the minimum fixture wire size that shall be permitted?

• 12 AWG
• 14 AWG
• 16 AWG
• 18 AWG

NEC Reference: NEC 402.6

Question 2: What size of over current protection device is required for a 24 ampere continuous load where the ambient temperature is 75 ⁰C?

• 30 amperes
• 24 amperes
• 28 ampers
• 26 amperes

NEC Reference: NEC 210.20(A)

Question 3: In multiple parallel circuit paths, the current will always take the path of ...............

• least resistance
• high resistance
• high voltage
• low voltage

Question 4: As mentioned in NEC, a multifamily dwelling unit is the one that contains …………….

• Two or more dwelling units
• Three or more dwelling units
• More than one dwelling unit
• More than two dwelling units

Question 5: What size service conductors are required for a dwelling load with a calculated load is 190 A. The service disconnect breaker is rated at 200 A?

• 1/0 AWG
• 2/0 AWG
• 3/0 AWG
• 4/0 AWG

NEC Reference: NEC 310.15(B)(16)

Question 6: A 400 breaker protects a set of 450 kcmil feeder conductors. A feeder fed from 450 kcmil feeder that supply disconnects with 25 A over current device. What is the minimum size conductor for these tap?

• 8 AWG
• 6 AWG
• 4 AWG
• 16 AWG

NEC Reference: NEC 310.15(B)(16)

Question 7: Which is the minimum size copper conductor is required for the grounding electrode conductor (GEC) connected to a ground rod

• 6 AWG
• 8 AWG
• 4 AWG
• 16 AWG

NEC Reference: NEC 250.166(A)

Question 8: What is the maximum size over current device is required for a 4200 W, 240 V electric water heater connected in a building.

• 25 A
• 30 A
• 35 A
• 40 A

NEC Reference: NEC 422.11(E)

Question 9: What is the maximum allowable conductor fill for 4in * 4 in wireway?

• 16 sq in
• 8 sq in
• 3.2 sq in
• 4.8 sq in

NEC Reference: NEC 376.22(A)

Question 10: How many 10 AWG RHH conductors can be installed in trade size ¾ EMT?

• 3 conductors
• 5 conductors
• 6 conductors
• 8 conductors

Question 11: All 125 volt through 250 volt receptacles installed outdoors at a dwelling unit require:

• GFCI protection
• AFCI protection only
• No special protection
• A dedicated neutral only

NEC Reference: NEC 210.8(A)(3)

Question 12: For overhead spans up to 50 feet in length and up to 600 volts, the minimum size copper conductor permitted is:

• 14 AWG
• 12 AWG
• 10 AWG
• 6 AWG

NEC Reference: NEC 225.6(A)(1)

Question 13: NEC 230.43 lists the wiring methods permitted for service-entrance conductors. Which of the following is one of the listed permitted methods?

• Rigid metal conduit
• Open knob-and-tube wiring
• Uninsulated bare wire in air
• Garden-grade extension cord

NEC Reference: NEC 230.43

Question 14: Cartridge fuseholders of the 0-6000 ampere class must be designed so that it is difficult to:

• Insert a fuse with a higher ampere rating than intended
• Remove the fuse for replacement
• Read the fuse ampere rating
• Insert any fuse at all

NEC Reference: NEC 240.60(B)

Question 15: Grounded electrical systems are connected to the earth to limit the voltage imposed by lightning, line surges, or unintentional contact with:

• Higher-voltage lines
• Low-voltage doorbell wiring
• Telephone lines only
• It has no protective purpose

NEC Reference: NEC 250.4(A)(1)

Question 16: A metal raceway or enclosure containing a grounding electrode conductor must be:

• Electrically continuous and bonded at each end
• Left isolated and ungrounded
• Insulated from the conductor inside
• Not permitted at all

NEC Reference: NEC 250.86

Question 17: Where electrical installations pass through fire-resistance-rated walls, floors, or ceilings, the openings must be firestopped using methods that:

• Maintain the fire-resistance rating of the assembly
• It does not matter, any gap is acceptable
• Only cosmetic caulking is needed
• Firestopping is never required

NEC Reference: NEC 300.21

Question 18: Conductors feeding through a cabinet, cutout box, or meter socket enclosure that are not connected to equipment in the enclosure are permitted only if the conductor fill does not exceed what percentage of the cross-sectional area?

• 40 %
• 20 %
• 60 %
• 100 %

NEC Reference: NEC 312.8

Question 19: Per NEC Table 314.16(B), each 12 AWG conductor counted in a box fill calculation requires a volume allowance of:

• 2.0 in3
• 2.25 in3
• 2.5 in3
• 3.0 in3

NEC Reference: NEC Table 314.16(B)

Question 20: Type MC (metal-clad) cable is permitted for use in which of the following applications, unlike standard Type AC cable?

• Direct burial (when listed for the purpose)
• It has no permitted uses
• Only inside a finished dry attic
• Only as a grounding conductor

NEC Reference: NEC 330.10

Question 21: Rigid PVC conduit runs must be provided with expansion fittings to compensate for thermal expansion and contraction where the length change is expected to be greater than:

• 1/4 inch
• 2 inches
• 6 inches
• 1 foot

NEC Reference: NEC 352.44

Question 22: A switch or circuit breaker is generally not permitted to disconnect the grounded conductor of a circuit unless it:

• Simultaneously disconnects all conductors of the circuit
• Is painted a special color
• Is rated for 480 volts
• This is always permitted with no restriction

NEC Reference: NEC 404.2(A)

Question 23: Receptacles, cord connectors, and attachment plugs must be rated in amperes and:

• Volts
• Ohms only
• Watts only
• No rating markings are required

NEC Reference: NEC 406.3(A)

Question 24: A portable luminaire connected by a flexible cord must terminate the cord in:

• A polarized or grounding-type attachment plug
• Bare exposed wire ends
• A wire nut only
• No termination is required

NEC Reference: NEC 410.62(A)

Question 25: For a permanently connected motor-operated appliance with a rating above 1/8 horsepower, the branch-circuit switch or circuit breaker is permitted to serve as the disconnecting means when it is:

• Within sight, or lockable in the open position
• Any breaker anywhere in the building
• No disconnecting means is ever needed
• Only a cord-and-plug is acceptable

NEC Reference: NEC 422.31(B)

Question 26: Fixed electric space-heating equipment must be provided with a means to disconnect the heater, motor controller(s), and supplementary overcurrent devices from all ungrounded conductors. This disconnect must be:

• Within sight, or lockable in the open position
• Located only at the utility meter
• Not required for fixed heaters
• Located inside the heater cabinet, hidden

NEC Reference: NEC 424.19

Question 27: A motor controller must have a horsepower rating not lower than:

• The horsepower rating of the motor
• Half the motor horsepower
• It does not need a rating
• Only the voltage matters, not horsepower

NEC Reference: NEC 430.83

Question 28: Branch-circuit conductors supplying a single motor-compressor must have an ampacity of not less than what percentage of the motor-compressor rated-load current or branch-circuit selection current?

• 100 %
• 115 %
• 125 %
• 150 %

NEC Reference: NEC 440.32

Question 29: 125 volt, 15 and 20 ampere receptacle outlets that are a part of a portable generator must have which protection?

• GFCI protection
• AFCI protection only
• No protection is required on generators
• Surge protection only

NEC Reference: NEC 445.20

Question 30: For a dry-type transformer 600 volts or less, protected only on the primary side, NEC Table 450.3(B) generally limits the primary overcurrent device to what maximum percentage of rated primary current (for primary current 9 amperes or more)?

• 125 %
• 167 %
• 250 %
• 300 %

NEC Reference: NEC Table 450.3(B)