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NEC 2020 Code Questions Practice Test 18

Free NEC 2020 practice test with 30 questions on receptacles, switches, cords, conduit, and motor overcurrent rules. Plain-English questions with full explanations.

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This NEC 2020 Code Questions Practice Test 18 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 18 — Question List

Question 1: In a dwelling bathroom, a receptacle must be within what distance of the outside edge of a basin?

1 foot
3 feet
6 feet
10 feet

NEC Reference: NEC 210.52(D)

Question 2: A one-family dwelling needs at least one grade-level receptacle at:

Both front and back
The garage only
Nowhere outdoors
The roof only

NEC Reference: NEC 210.52(E)(1)

Question 3: If a box has no grounding means, a non-grounding receptacle can be replaced with another:

Non-grounding-type receptacle
A grounding type with a false ground shown
Nothing, replacement is banned
A 240 volt receptacle only

NEC Reference: NEC 406.4(D)(1)

Question 4: A non-grounding receptacle can also be replaced with a GFCI receptacle marked:

"No Equipment Ground"
"Fully Grounded"
No marking is needed
"GFCI Not Required"

NEC Reference: NEC 406.4(D)(2)

Question 5: A receptacle mounting yoke should be held how firmly against the wall?

Rigidly
Loosely
It does not matter
With tape only

NEC Reference: NEC 406.5

Question 6: To control a motor rated over 2 horsepower, a switch must generally be:

Horsepower rated
Any general-use switch
Never used for motors
Rated in ohms only

NEC Reference: NEC 404.14(D)

Question 7: A switch installed outdoors or in a wet location needs an enclosure that is:

Weatherproof
Left open
Wooden
No enclosure needed

NEC Reference: NEC 404.4

Question 8: A snap switch installed in a metal box must be:

Grounded
Insulated from the box always
Left ungrounded
Loose in the box

NEC Reference: NEC 404.11

Question 9: A portable handlamp needs a hard-usage cord and:

A substantial guard
No guard at all
A paper shade
A second unused cord

NEC Reference: NEC 410.62(C)

Question 10: The largest trade size of EMT permitted by the NEC is:

2 inches
4 inches
6 inches
There is no limit

NEC Reference: NEC 358.20

Question 11: An EMT run between pull points must not have more than the equal of how many quarter bends?

One
Four
Ten
There is no limit

NEC Reference: NEC 358.26

Question 12: Liquidtight flexible metal conduit is generally supported at intervals not more than:

2 feet
4 1/2 feet
10 feet
15 feet

NEC Reference: NEC 350.30

Question 13: Intermediate metal conduit (IMC) must be supported at intervals not more than:

5 feet
10 feet
15 feet
20 feet

NEC Reference: NEC 342.30

Question 14: Rigid PVC conduit is commonly used in which environment, when suitably listed?

Corrosive and wet locations
Only inside a dry attic
It has no permitted use
Only for grounding

NEC Reference: NEC 352.10

Question 15: Where flexibility is needed after installation, FMC can be left unsupported for up to:

3 feet
6 feet
10 feet
12 feet

NEC Reference: NEC 348.30(A)

Question 16: The conductors in a wireway must not fill more than what percent of the wireway area?

20 %
40 %
53 %
75 %

NEC Reference: NEC 376.22(A)

Question 17: An auxiliary gutter must not extend more than what distance beyond the equipment it supplements?

10 feet
30 feet
100 feet
There is no limit

NEC Reference: NEC 366.12

Question 18: Conductors that just pass through a cabinet, without connecting to equipment there, must not fill more than what percent of the space?

20 %
40 %
60 %
100 %

NEC Reference: NEC 312.8

Question 19: For a general motor, the maximum dual-element (time-delay) fuse rating is what percent of full-load current?

150 %
175 %
250 %
300 %

NEC Reference: NEC Table 430.52

Question 20: For a general motor, an inverse-time breaker is generally capped at what percent of full-load current?

150 %
175 %
250 %
400 %

NEC Reference: NEC Table 430.52

Question 21: A motor controller must have a horsepower rating not lower than the:

Motor horsepower rating
Half the motor horsepower
It needs no rating
Only voltage matters

NEC Reference: NEC 430.83

Question 22: When fuses are used for motor overload protection, how many are needed per ungrounded conductor?

One
Zero, none are needed
Three, always
Only in the neutral

NEC Reference: NEC 430.36

Question 23: After an overload trip, a motor automatically restarting on its own is:

Generally prohibited, unless listed for it
Always required
Never addressed by the NEC
Required for small motors only

NEC Reference: NEC 430.43

Question 24: The motor nameplate current is used for setting the overload protection, while the NEC tables are used for:

Conductor and OCPD sizing
Nothing else
Paint color
Building permits

NEC Reference: NEC 430.6(A)(1)

Question 25: A disconnecting means for a motor controller must be located:

Within sight of the controller
Anywhere in the building
In a different building
Not required

NEC Reference: NEC 430.102(A)

Question 26: Two motors, 10 amperes and 15 amperes full-load current, share a feeder. Using 125% for the larger motor plus the smaller motor's current, what is the minimum feeder ampacity?

25 amperes
28.75 amperes
31.25 amperes
18.75 amperes

NEC Reference: NEC 430.24

Question 27: The nameplate of a hermetic motor-compressor must show the rated-load current or:

Branch-circuit selection current
The installer's license number
No additional marking
The permit number

NEC Reference: NEC 440.4(A)

Question 28: A single-phase room air conditioner cord must include a factory-installed leakage-current detection device as part of:

The attachment plug or cord
The main panel only
Nothing is required
A separate wall switch

NEC Reference: NEC 440.65

Question 29: Multimotor air-conditioning equipment branch-circuit protection is generally capped at what percent of the largest motor or load, plus the others?

175 %
225 %
300 %
400 %

NEC Reference: NEC 440.22(B)

Question 30: Short-circuit and ground-fault protection for a single motor-compressor branch circuit must not exceed what percent of rated-load current, in most cases?

125 %
175 %
225 %
300 %

NEC Reference: NEC 440.22(A)

NEC 2020 Code Questions Practice Test 18

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NEC 2020 Code Questions Practice Test 18

How this test works

How to Use This Practice Test

Student Reviews

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NEC 2020 Code Questions Practice Test 18 — Question List

Question 1: In a dwelling bathroom, a receptacle must be within what distance of the outside edge of a basin?

Question 2: A one-family dwelling needs at least one grade-level receptacle at:

Question 3: If a box has no grounding means, a non-grounding receptacle can be replaced with another:

Question 4: A non-grounding receptacle can also be replaced with a GFCI receptacle marked:

Question 5: A receptacle mounting yoke should be held how firmly against the wall?

Question 6: To control a motor rated over 2 horsepower, a switch must generally be:

Question 7: A switch installed outdoors or in a wet location needs an enclosure that is:

Question 8: A snap switch installed in a metal box must be:

Question 9: A portable handlamp needs a hard-usage cord and:

Question 10: The largest trade size of EMT permitted by the NEC is:

Question 11: An EMT run between pull points must not have more than the equal of how many quarter bends?

Question 12: Liquidtight flexible metal conduit is generally supported at intervals not more than:

Question 13: Intermediate metal conduit (IMC) must be supported at intervals not more than:

Question 14: Rigid PVC conduit is commonly used in which environment, when suitably listed?

Question 15: Where flexibility is needed after installation, FMC can be left unsupported for up to:

Question 16: The conductors in a wireway must not fill more than what percent of the wireway area?

Question 17: An auxiliary gutter must not extend more than what distance beyond the equipment it supplements?

Question 18: Conductors that just pass through a cabinet, without connecting to equipment there, must not fill more than what percent of the space?

Question 19: For a general motor, the maximum dual-element (time-delay) fuse rating is what percent of full-load current?

Question 20: For a general motor, an inverse-time breaker is generally capped at what percent of full-load current?

Question 21: A motor controller must have a horsepower rating not lower than the:

Question 22: When fuses are used for motor overload protection, how many are needed per ungrounded conductor?

Question 23: After an overload trip, a motor automatically restarting on its own is:

Question 24: The motor nameplate current is used for setting the overload protection, while the NEC tables are used for:

Question 25: A disconnecting means for a motor controller must be located:

Question 26: Two motors, 10 amperes and 15 amperes full-load current, share a feeder. Using 125% for the larger motor plus the smaller motor's current, what is the minimum feeder ampacity?

Question 27: The nameplate of a hermetic motor-compressor must show the rated-load current or:

Question 28: A single-phase room air conditioner cord must include a factory-installed leakage-current detection device as part of:

Question 29: Multimotor air-conditioning equipment branch-circuit protection is generally capped at what percent of the largest motor or load, plus the others?

Question 30: Short-circuit and ground-fault protection for a single motor-compressor branch circuit must not exceed what percent of rated-load current, in most cases?

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