NEC_PRACTICE NEC 2020

NEC 2020 Code Questions Practice Test 14

Free NEC 2020 practice test with 30 questions on grounding, ampacity basics, switches, luminaires, and appliances. Plain-English questions with full explanations.

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This NEC 2020 Code Questions Practice Test 14 has 30 questions with detailed answers and NEC references. Take the full test, review every wrong answer, and look up the NEC article it references before moving on.

Tip: Mixed-format test — questions jump between topics just like the real exam. Don't spend more than 90 seconds on any one question.

  • Topics covered: All NEC chapters — branch circuits, grounding, conductors, wiring methods, motors, and more.
  • Passing score: Aim for 80%+ consistently before scheduling your exam.
  • Questions: 30 multiple-choice, one correct answer each
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NEC 2020 Code Questions Practice Test 14 — Question List

Question 1: A lighting and appliance panelboard must be protected by an overcurrent device rated no higher than the panelboard, except when the panel is rated:

  • 200 amperes or more
  • 400 amperes or more
  • 100 amperes or more
  • There is no exception

NEC Reference: NEC 408.36

Question 2: The connection of a grounding electrode conductor to its electrode must be:

  • Accessible
  • Always buried and hidden
  • Painted over
  • Sealed inside concrete with no exception

NEC Reference: NEC 250.68(A)

Question 3: Where exposed, a grounding electrode conductor must be protected if it is exposed to:

  • Physical damage
  • Sunlight only
  • Cold weather only
  • It never needs protection

NEC Reference: NEC 250.64(B)

Question 4: A circuit is protected by a 20 ampere breaker. What is the minimum copper equipment grounding conductor size?

  • 14 AWG
  • 12 AWG
  • 10 AWG
  • 8 AWG

NEC Reference: NEC 250.122

Question 5: Which of the following is a recognized type of equipment grounding conductor?

  • Rigid metal conduit
  • A garden hose
  • A wood beam
  • A telephone wire

NEC Reference: NEC 250.118

Question 6: An isolated ground receptacle is used to reduce which problem for sensitive equipment?

  • Electrical noise
  • Water leaks
  • Low voltage only
  • It has no purpose

NEC Reference: NEC 250.146(D)

Question 7: The intersystem bonding termination at a service is used to connect:

  • Communication system grounds
  • Nothing, it has no purpose
  • The gas meter only
  • A lightning rod system only

NEC Reference: NEC 250.94

Question 8: The effective ground-fault current path is a low-impedance path built to help the overcurrent device work during a:

  • Ground fault
  • Normal daily use
  • Power outage
  • It has no purpose

NEC Reference: NEC 250.4(A)(5)

Question 9: Grounding an electrical system helps limit voltage caused by lightning, line surges, and unintended contact with:

  • Higher-voltage lines
  • Low-voltage doorbell wire
  • Telephone lines only
  • It has no safety purpose

NEC Reference: NEC 250.4(A)(1)

Question 10: An AC system of 50 to 1000 volts must be grounded if it can be grounded so the voltage to ground does not go above:

  • 120 volts
  • 150 volts
  • 240 volts
  • 300 volts

NEC Reference: NEC 250.20(B)

Question 11: In a balanced 3-wire circuit, the neutral conductor is not counted as current-carrying because it only carries:

  • The unbalanced current
  • The full current of both hot wires
  • Double the hot wire current
  • No current at all, ever

NEC Reference: NEC 310.15(A)(3)

Question 12: The standard NEC ampacity tables are based on an ambient temperature of:

  • 0 C
  • 30 C
  • 60 C
  • 90 C

NEC Reference: NEC 310.14

Question 13: When more than 3 current-carrying conductors are bundled in a raceway, the conductor ampacity must be:

  • Adjusted downward
  • Left unchanged
  • Increased
  • Doubled

NEC Reference: NEC Table 310.15(C)(1)

Question 14: Under Condition 2 (grounded parts on the other side) at 0-150 volts to ground, the working space depth needed is:

  • 2 feet
  • 3 feet
  • 4 feet
  • 5 feet

NEC Reference: NEC 110.26(A)(1)

Question 15: For a circuit rated 100 amperes or less, conductors are generally sized using which terminal temperature column?

  • 60 C
  • 75 C
  • 90 C
  • 105 C

NEC Reference: NEC 110.14(C)(1)(a)

Question 16: A flexible cord is permitted for:

  • Connecting a portable lamp
  • Permanent building wiring
  • Running through a wall
  • Replacing a raceway in new work

NEC Reference: NEC 400.10

Question 17: Flexible cords are not permitted to run through:

  • Holes in walls, ceilings, or floors
  • An open coil on the floor
  • A power tool
  • A holiday light display

NEC Reference: NEC 400.8

Question 18: Flexible cords must generally be used without:

  • A splice or tap
  • A plug
  • Insulation
  • Any length limit

NEC Reference: NEC 400.13

Question 19: Receptacles must be rated in amperes and:

  • Volts
  • Ohms only
  • Watts only
  • No rating is required

NEC Reference: NEC 406.3(A)

Question 20: An AC general-use snap switch can control a load up to:

  • Its own ampere rating
  • Half its ampere rating
  • Twice its ampere rating
  • There is no limit

NEC Reference: NEC 404.14(A)

Question 21: A metal faceplate on a switch or receptacle must be:

  • Grounded
  • Painted only
  • Insulated from ground
  • Left loose

NEC Reference: NEC 404.9(B)

Question 22: All light fixtures (luminaires) installed under the NEC must be:

  • Listed
  • Homemade
  • Exempt from all rules
  • Approved by the homeowner only

NEC Reference: NEC 410.6

Question 23: A portable light fixture connected by cord must end in:

  • A polarized or grounding-type plug
  • Bare wire ends
  • A wire nut
  • No end connection at all

NEC Reference: NEC 410.62(A)

Question 24: A recessed light fixture that will touch insulation must be listed as Type:

  • Type IC
  • Type NM
  • Type AC
  • No listing is needed

NEC Reference: NEC 410.116(A)

Question 25: A fixed storage-type water heater of 120 gallons or less is treated, for circuit sizing, as a:

  • Continuous load
  • Non-continuous load, always
  • It is exempt from sizing rules
  • A momentary load

NEC Reference: NEC 422.13

Question 26: Every fixed appliance must have a way to disconnect it from all ungrounded conductors, which can be provided by:

  • A breaker, switch, or attachment plug
  • The nameplate alone
  • Nothing is ever required
  • A fused disconnect only

NEC Reference: NEC 422.30

Question 27: A motor is marked with a service factor of 1.15 or greater. What is the maximum overload setting allowed?

  • 100 %
  • 115 %
  • 125 %
  • 150 %

NEC Reference: NEC 430.32(A)(1)

Question 28: A motor must be placed where it gets enough air flow and where maintenance can be:

  • Easily done
  • Never performed
  • Done only by the factory
  • Not a factor at all

NEC Reference: NEC 430.14(A)

Question 29: For a small cord-and-plug room air conditioner, the disconnect requirement can be met by:

  • The attachment plug and receptacle
  • A separate breaker only
  • Cutting power at the meter
  • No disconnect is ever provided

NEC Reference: NEC 440.63

Question 30: A motor-compressor has a rated-load current of 16 amperes. What is the minimum branch-circuit conductor ampacity?

  • 16 amperes
  • 20 amperes
  • 24 amperes
  • 32 amperes

NEC Reference: NEC 440.32

EXAM CARD NEC_PRACTICE
Questions30
Time limit45 min
Pass score70%
Code editionNEC 2020
DifficultyIntermediate
Last reviewedJun 2026

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Source: NEC 2026 (NFPA 70)