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NEC 2023 Code Questions Practice Test 18

Free NEC 2023 practice test with 30 questions on low-voltage circuits, communications wiring, and fire alarm systems. Plain-English questions with full explanations.

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This NEC 2023 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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45 min

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NEC 2023 Code Questions Practice Test 18 — Question List

Question 1: A Class 1 remote-control circuit is generally limited to a voltage of not more than:

600 volts
30 volts
5000 volts
There is no limit

NEC Reference: NEC 725.41

Question 2: Class 2 power sources are limited so that the output poses:

A reduced fire and shock risk
The same risk as a service conductor
No output at all
An increased risk always

NEC Reference: NEC 725.121

Question 3: Class 2 and Class 3 circuit cables must generally be kept separated from electric light and power conductors unless they are:

Properly separated or in a listed cable
Twisted together with no separation
Never allowed near each other at all
Painted the same color

NEC Reference: NEC 725.136

Question 4: Fire alarm circuits are generally classified as either power-limited or:

Non-power-limited
Wireless only
Decorative only
There is no other type

NEC Reference: NEC 760.121

Question 5: Fire alarm cables installed in ducts, plenums, and other spaces used for environmental air must be:

Plenum-rated
Any random cable
Uninsulated bare wire
Not permitted at all

NEC Reference: NEC 760.176

Question 6: Certain fire alarm circuits that must keep working during a fire need a level of:

Circuit integrity (survivability)
Decoration
No requirement at all
Random color coding only

NEC Reference: NEC 760.31

Question 7: A primary protector on a communications circuit must be grounded, and the grounding conductor should be:

As short and straight as practicable
As long and curvy as possible
Completely removed
Made of rope

NEC Reference: NEC 800.100

Question 8: Outside communications wires must be kept separated from open power conductors of over 300 volts by at least:

6 feet
1 inch
50 feet
No separation is needed

NEC Reference: NEC 800.44

Question 9: The metallic sheath of a coaxial cable (CATV) entering a building must be:

Grounded
Left floating with no ground
Removed
Painted

NEC Reference: NEC 820.100

Question 10: NEC Article 770 covers optical fiber cables, which:

Carry light signals, not electricity
Carry only 480-volt power
Are always bare copper
Are the same as service conductors

NEC Reference: NEC 770.1

Question 11: A network-powered broadband communications system is one where power for the system comes from:

The communications network itself
A car battery only
Nowhere, it needs no power
A separate diesel generator always

NEC Reference: NEC 830.2

Question 12: The accessible portion of abandoned communications cable must be:

Removed
Left in place forever, always
Painted red
Reconnected to power

NEC Reference: NEC 800.25

Question 13: The rule requiring removal of abandoned cable applies to which of these systems?

Class 2 and Class 3 remote-control circuits
Only garden hoses
Nothing, this rule does not exist
Only water pipes

NEC Reference: NEC 725.25

Question 14: Security alarm system wiring in a home is generally installed under the rules for:

Class 1, 2, or 3 signaling circuits
Article 250 grounding rules alone
Nothing, it is unregulated
Article 90 alone

NEC Reference: NEC 725.1

Question 15: A typical residential doorbell transformer supplies a circuit that is usually classified as:

Class 2
480 volts three-phase
A service conductor
A feeder

NEC Reference: NEC 725.60

Question 16: Communications cables must be listed and marked to show they are suitable for their installed:

Use and location
Favorite color
Nothing, marking is not required
The installer's initials only

NEC Reference: NEC 800.179

Question 17: An antenna mast and metal structure must be:

Grounded
Left floating in the air electrically
Painted only
Removed after install

NEC Reference: NEC 810.21

Question 18: Outdoor antenna and lead-in conductors must be kept clear of all:

Power and light conductors
Tree branches only
Nothing, clearance is not required
Only water pipes

NEC Reference: NEC 810.18

Question 19: The grounding conductor for a communications system should connect to the building's grounding electrode system or to:

A qualifying grounding electrode
A random tree
Nothing, grounding is optional
A fence post only

NEC Reference: NEC 800.100(A)

Question 20: The branch circuit supplying a fire alarm control unit must be supervised, meaning:

Loss of power is detected and signaled
Nobody is ever informed of a problem
The circuit is never checked
It automatically shuts down permanently

NEC Reference: NEC 760.41

Question 21: The disconnecting means for the branch circuit supplying a fire alarm system must be:

Identified and secured
Left completely unmarked
Removed entirely
Painted invisible

NEC Reference: NEC 760.30

Question 22: Fire alarm circuit conductors and cables must be supported so they are protected from:

Physical damage
Sunlight only
Nothing, support is optional
Cold weather only

NEC Reference: NEC 760.24

Question 23: Class 2 and Class 3 cables must not be placed in the same raceway with conductors of electric light, power, or Class 1 circuits unless:

A permitted exception applies
It is always allowed with no rule
It is never allowed under any condition
The wires are the same color

NEC Reference: NEC 725.136(B)

Question 24: Instrumentation tray cable (Type ITC) is generally used in industrial facilities for:

Instrumentation and control circuits
Kitchen countertop receptacles
Swimming pool lighting only
Nothing, it has no defined use

NEC Reference: NEC 727.4

Question 25: Amateur radio and receiving station equipment metal enclosures must be:

Grounded
Left ungrounded always
Painted gold
Removed

NEC Reference: NEC 810.15

Question 26: NEC Article 830 covers network-powered broadband communications systems, providing:

Cabling and protection requirements
Kitchen wiring rules
Pool bonding rules
Nothing useful

NEC Reference: NEC 830.1

Question 27: Many closed-circuit television (CCTV) camera systems in homes use low-voltage wiring under:

Article 725
Article 680 only
Article 550 only
No article covers this

NEC Reference: NEC 725.1

Question 28: Communications wires and cables installed in a raceway with electric light or power conductors must be:

Separated as required
Mixed freely with no rule
Removed completely
Painted a matching color

NEC Reference: NEC 800.110

Question 29: A communications grounding conductor is generally permitted to be as small as:

14 AWG copper
4/0 AWG copper only
4 AWG aluminum only
No size is specified

NEC Reference: NEC 800.100(A)(4)

Question 30: The main purpose of the National Electrical Code is the practical safeguarding of persons and property from hazards arising from:

The use of electricity
Loud noises
Bad weather only
Nothing at all

NEC Reference: NEC 90.1(A)

NEC 2023 Code Questions Practice Test 18

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NEC 2023 Code Questions Practice Test 18

How this test works

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Student Reviews

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NEC 2023 Code Questions Practice Test 18 — Question List

Question 1: A Class 1 remote-control circuit is generally limited to a voltage of not more than:

Question 2: Class 2 power sources are limited so that the output poses:

Question 3: Class 2 and Class 3 circuit cables must generally be kept separated from electric light and power conductors unless they are:

Question 4: Fire alarm circuits are generally classified as either power-limited or:

Question 5: Fire alarm cables installed in ducts, plenums, and other spaces used for environmental air must be:

Question 6: Certain fire alarm circuits that must keep working during a fire need a level of:

Question 7: A primary protector on a communications circuit must be grounded, and the grounding conductor should be:

Question 8: Outside communications wires must be kept separated from open power conductors of over 300 volts by at least:

Question 9: The metallic sheath of a coaxial cable (CATV) entering a building must be:

Question 10: NEC Article 770 covers optical fiber cables, which:

Question 11: A network-powered broadband communications system is one where power for the system comes from:

Question 12: The accessible portion of abandoned communications cable must be:

Question 13: The rule requiring removal of abandoned cable applies to which of these systems?

Question 14: Security alarm system wiring in a home is generally installed under the rules for:

Question 15: A typical residential doorbell transformer supplies a circuit that is usually classified as:

Question 16: Communications cables must be listed and marked to show they are suitable for their installed:

Question 17: An antenna mast and metal structure must be:

Question 18: Outdoor antenna and lead-in conductors must be kept clear of all:

Question 19: The grounding conductor for a communications system should connect to the building's grounding electrode system or to:

Question 20: The branch circuit supplying a fire alarm control unit must be supervised, meaning:

Question 21: The disconnecting means for the branch circuit supplying a fire alarm system must be:

Question 22: Fire alarm circuit conductors and cables must be supported so they are protected from:

Question 23: Class 2 and Class 3 cables must not be placed in the same raceway with conductors of electric light, power, or Class 1 circuits unless:

Question 24: Instrumentation tray cable (Type ITC) is generally used in industrial facilities for:

Question 25: Amateur radio and receiving station equipment metal enclosures must be:

Question 26: NEC Article 830 covers network-powered broadband communications systems, providing:

Question 27: Many closed-circuit television (CCTV) camera systems in homes use low-voltage wiring under:

Question 28: Communications wires and cables installed in a raceway with electric light or power conductors must be:

Question 29: A communications grounding conductor is generally permitted to be as small as:

Question 30: The main purpose of the National Electrical Code is the practical safeguarding of persons and property from hazards arising from:

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