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NEC 2023 Code Questions Practice Test 19

Free NEC 2023 practice test with 30 mixed-review questions covering transformers, motors, industrial control, and general code knowledge. Plain-English questions with full explanations.

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How to Use This Practice Test

This NEC 2023 Code Questions Practice Test 19 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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45 min

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NEC 2023 Code Questions Practice Test 19 — Question List

Question 1: For a transformer 1000 volts or less with primary protection only, the overcurrent device is generally sized at not more than what percent of primary current?

125 %
25 %
500 %
No protection is needed

NEC Reference: NEC Table 450.3(B)

Question 2: Transformer secondary conductors are often sized under special "tap" rules found in:

NEC 240.21(C)
NEC 90.1
NEC 110.3
No such rule exists

NEC Reference: NEC 240.21(C)

Question 3: Dry-type transformers rated over a certain kVA installed indoors generally require a fire-resistant:

Transformer room
Nothing at all
Wooden shed
Cardboard enclosure

NEC Reference: NEC 450.21

Question 4: A continuous-duty motor rated more than 1 horsepower generally needs overload protection sized at what percent of full-load current for a service factor of 1.15 or more?

125 %
25 %
500 %
0 %

NEC Reference: NEC 430.32(A)(1)

Question 5: When a motor disconnect is opened, the motor control circuit should generally also be:

Disconnected from its source
Left fully energized
Turned up to full speed
Ignored completely

NEC Reference: NEC 430.74

Question 6: A motor controller must have a horsepower rating that is:

Not lower than the motor rating
Always lower than the motor
Random, it does not matter
Zero

NEC Reference: NEC 430.83

Question 7: An individual disconnecting means must generally be provided for each motor and located:

Within sight of the motor
On a different property
Nowhere, none is required ever
Only in a locked vault far away

NEC Reference: NEC 430.102(A)

Question 8: An industrial control panel must be marked with the manufacturer's name and:

Voltage, current, and short-circuit rating
Nothing else at all
The installer's birthday
A random logo only

NEC Reference: NEC 409.110

Question 9: A capacitor must be provided with a means to drain the stored charge, reducing residual voltage within:

A specified short time period
Never, charge stays forever
10 years
It is not addressed by the NEC

NEC Reference: NEC 460.6

Question 10: An overcurrent device is generally required for a capacitor to protect against:

Short circuits and overcurrent
Nothing, none is ever needed
Rain only
Sunlight only

NEC Reference: NEC 460.8(B)

Question 11: A vehicle-mounted generator frame may serve as the grounding electrode when the generator supplies:

Equipment mounted on or bonded to the vehicle
An entire apartment building
A different city
Nothing at all

NEC Reference: NEC 250.34(A)

Question 12: A "qualified person" under the NEC is one who has the skills and knowledge related to:

The equipment and its hazards
Cooking recipes
Nothing in particular
Painting techniques

NEC Reference: NEC Article 100

Question 13: "Identified (as applied to equipment)" means recognized as suitable for:

The specific purpose
Any random purpose
No purpose at all
Decoration only

NEC Reference: NEC Article 100

Question 14: The "authority having jurisdiction" (AHJ) is the organization responsible for:

Enforcing the Code
Selling equipment
Nothing at all
Cooking inspections only

NEC Reference: NEC Article 100

Question 15: Equipment that is "listed" appears in a list published by an organization that evaluates:

Products or materials for safety
Restaurant menus
Nothing relevant
Paint colors

NEC Reference: NEC Article 100

Question 16: For reasonable efficiency, combined voltage drop on a feeder and branch circuit is generally recommended not to exceed:

5 %
50 %
0.5 %
100 %

NEC Reference: NEC 210.19(A) Informational Note

Question 17: The ampacity of a conductor is generally found using ampacity tables together with:

Adjustment and correction factors
The installer's guess
Nothing else
The color of insulation only

NEC Reference: NEC 310.14

Question 18: The ampacity of a conductor connected to a terminal must not exceed the terminal's:

Temperature rating
Color
Weight
Brand name

NEC Reference: NEC 110.14(C)

Question 19: Terminals for aluminum conductors must be marked and used according to manufacturer instructions to avoid:

Corrosion or connection failure
Extra shine
Nothing at all
A pleasant smell

NEC Reference: NEC 110.14(B)

Question 20: When conductors are run in parallel to share current, the minimum conductor size permitted is generally:

1/0 AWG
14 AWG
18 AWG
There is no minimum

NEC Reference: NEC 310.10(G)

Question 21: Paralleled conductors in each phase must be the same length and:

Same material, size, and insulation
Different sizes always
Different materials always
It does not matter at all

NEC Reference: NEC 310.10(G)(1)

Question 22: The feeder or service neutral load is generally calculated as the maximum unbalance of the:

Load between neutral and ungrounded conductor
The color of the wire
The homeowner's preference
Nothing at all

NEC Reference: NEC 220.61

Question 23: General lighting load for dwelling units is calculated at a set amount of volt-amperes per:

Square foot of floor area
Household pet
Window count only
Nothing, it is a fixed number always

NEC Reference: NEC 220.42

Question 24: A demand factor is applied to certain dwelling loads because not all loads are likely to operate:

At the same time
Ever, under any condition
On weekends only
Never, they are always all off

NEC Reference: NEC Table 220.42

Question 25: NEC 220.82 provides an optional method for calculating the feeder or service load of a:

Dwelling unit
Gas station canopy
Swimming pool only
Nothing at all

NEC Reference: NEC 220.82

Question 26: A 20-ampere branch circuit with multiple receptacle outlets generally has a maximum cord-and-plug load per receptacle of:

16 amperes
5 amperes
50 amperes
100 amperes

NEC Reference: NEC Table 210.21(B)(2)

Question 27: A single receptacle installed on an individual branch circuit must have an ampere rating not less than:

The branch-circuit rating
Half the branch-circuit rating
Zero
Any random rating

NEC Reference: NEC 210.21(B)(1)

Question 28: A separately derived system, such as one from a transformer secondary, generally needs its own:

System bonding jumper and grounding connection
No grounding at all
A different building entirely
Nothing extra

NEC Reference: NEC 250.30(A)

Question 29: A separately derived system is a premises wiring system whose power is derived from a source with no direct connection to:

Conductors of another supply system
The building foundation
The roof
Nothing relevant

NEC Reference: NEC Article 100

Question 30: Electrical equipment must be installed in a neat and workmanlike manner, which is a requirement found in:

NEC 110.12
NEC 90.9
NEC 250.1
There is no such requirement

NEC Reference: NEC 110.12

NEC 2023 Code Questions Practice Test 19

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NEC 2023 Code Questions Practice Test 19

How this test works

How to Use This Practice Test

Student Reviews

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NEC 2023 Code Questions Practice Test 19 — Question List

Question 1: For a transformer 1000 volts or less with primary protection only, the overcurrent device is generally sized at not more than what percent of primary current?

Question 2: Transformer secondary conductors are often sized under special "tap" rules found in:

Question 3: Dry-type transformers rated over a certain kVA installed indoors generally require a fire-resistant:

Question 4: A continuous-duty motor rated more than 1 horsepower generally needs overload protection sized at what percent of full-load current for a service factor of 1.15 or more?

Question 5: When a motor disconnect is opened, the motor control circuit should generally also be:

Question 6: A motor controller must have a horsepower rating that is:

Question 7: An individual disconnecting means must generally be provided for each motor and located:

Question 8: An industrial control panel must be marked with the manufacturer's name and:

Question 9: A capacitor must be provided with a means to drain the stored charge, reducing residual voltage within:

Question 10: An overcurrent device is generally required for a capacitor to protect against:

Question 11: A vehicle-mounted generator frame may serve as the grounding electrode when the generator supplies:

Question 12: A "qualified person" under the NEC is one who has the skills and knowledge related to:

Question 13: "Identified (as applied to equipment)" means recognized as suitable for:

Question 14: The "authority having jurisdiction" (AHJ) is the organization responsible for:

Question 15: Equipment that is "listed" appears in a list published by an organization that evaluates:

Question 16: For reasonable efficiency, combined voltage drop on a feeder and branch circuit is generally recommended not to exceed:

Question 17: The ampacity of a conductor is generally found using ampacity tables together with:

Question 18: The ampacity of a conductor connected to a terminal must not exceed the terminal's:

Question 19: Terminals for aluminum conductors must be marked and used according to manufacturer instructions to avoid:

Question 20: When conductors are run in parallel to share current, the minimum conductor size permitted is generally:

Question 21: Paralleled conductors in each phase must be the same length and:

Question 22: The feeder or service neutral load is generally calculated as the maximum unbalance of the:

Question 23: General lighting load for dwelling units is calculated at a set amount of volt-amperes per:

Question 24: A demand factor is applied to certain dwelling loads because not all loads are likely to operate:

Question 25: NEC 220.82 provides an optional method for calculating the feeder or service load of a:

Question 26: A 20-ampere branch circuit with multiple receptacle outlets generally has a maximum cord-and-plug load per receptacle of:

Question 27: A single receptacle installed on an individual branch circuit must have an ampere rating not less than:

Question 28: A separately derived system, such as one from a transformer secondary, generally needs its own:

Question 29: A separately derived system is a premises wiring system whose power is derived from a source with no direct connection to:

Question 30: Electrical equipment must be installed in a neat and workmanlike manner, which is a requirement found in:

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