Limited Energy Technician State
Licensing Exam Practice Exam 100
Questions And Correct Answers
(Verified Answers) Plus Rationales
2026 Q&A Instant Download Pdf
1. Which of the following systems is classified as a limited energy system?
A. 480V motor control circuit
B. 277V lighting circuit
C. Fire alarm signaling circuit
D. Medium-voltage distribution feeder
C. Fire alarm signaling circuit
Limited energy systems operate at lower voltages and power levels designed
to reduce shock and fire hazards. Fire alarm signaling circuits are commonly
classified as limited energy systems because they typically operate at low
voltage and current levels.
2. The primary purpose of a transformer in a low-voltage system is to:
A. Increase current flow only
B. Change voltage levels
C. Prevent grounding
D. Eliminate resistance
B. Change voltage levels
Transformers are electrical devices used to step voltage up or down through
electromagnetic induction. In limited energy systems, transformers commonly
,reduce standard building voltage to safer operating voltages such as 24V or
12V.
3. Which NEC article primarily governs fire alarm systems?
A. Article 250
B. Article 300
C. Article 760
D. Article 430
C. Article 760
NEC Article 760 covers installation requirements for fire alarm systems,
including wiring methods, power supplies, circuit separation, and equipment
installation standards.
4. Which NEC article covers Class 2 and Class 3 circuits?
A. Article 725
B. Article 770
C. Article 800
D. Article 820
A. Article 725
NEC Article 725 governs Class 1, Class 2, and Class 3 remote-control and
signaling circuits. Class 2 and Class 3 circuits are power-limited and operate
at lower energy levels.
5. A technician is installing a 24-V control circuit in a commercial building. The
circuit is supplied by a listed Class 2 power source. The technician wants to
route the conductors in the same raceway as 120-V branch-circuit conductors.
What is the primary code concern?
A. The Class 2 circuit must always be installed underground.
B. The 24-V circuit must be converted to a Class 1 circuit.
C. The conductors may require separation from the power conductors unless
the applicable NEC conditions for combining them are satisfied.
,D. The 120-V circuit must be reduced to 24 V.
C. The conductors may require separation from the power conductors unless
the applicable NEC conditions for combining them are satisfied.
Limited-energy conductors cannot simply be placed with higher-voltage
power conductors without satisfying the applicable separation and insulation
requirements. The classification of the circuit and the wiring method
determine what combinations are permitted.
6. A fire alarm technician is troubleshooting a notification circuit. The
measured resistance across the circuit is substantially higher than expected,
and several notification appliances are not operating. What is the most likely
problem?
A. A short circuit across the conductors
B. An open or high-resistance connection
C. Excessive grounding electrode resistance
D. An oversized transformer
B. An open or high-resistance connection
An open or high-resistance connection increases circuit resistance and can
prevent sufficient current from reaching downstream devices. A direct short
would normally produce a very low resistance.
7. A 24-V transformer supplies a control circuit drawing 2 A. Ignoring losses,
what is the approximate apparent power required from the transformer?
A. 12 VA
B. 24 VA
C. 48 VA
D. 96 VA
C. 48 VA
Using VA = V × A, 24V × 2A = 48VA.
, 8. A technician measures 24 V at the power supply but only 18 V at the
farthest control device under load. Which condition should be investigated
first?
A. Excessive voltage drop
B. Excessive grounding electrode resistance
C. Incorrect frequency
D. Excessive conductor insulation thickness
A. Excessive voltage drop
The six-volt difference under load strongly indicates voltage drop caused by
conductor resistance, excessive conductor length, inadequate conductor size,
or a poor connection.
9. A Class 2 circuit is extended through several junction boxes. Which
installation practice is most appropriate?
A. Leave all conductors unsupported between boxes.
B. Maintain proper conductor support and protect conductors from physical
damage.
C. Use ordinary extension cords permanently.
D. Remove all box covers after inspection.
B. Maintain proper conductor support and protect conductors from physical
damage.
Limited-energy wiring is still required to be installed in a workmanship-like
manner, with appropriate support and protection.
10. A technician is terminating a twisted-pair data cable. The cable's pairs are
untwisted several inches farther than necessary before termination. What is
the principal concern?
A. Increased conductor ampacity
B. Reduced electromagnetic performance and possible increased crosstalk
C. Increased insulation voltage rating
Licensing Exam Practice Exam 100
Questions And Correct Answers
(Verified Answers) Plus Rationales
2026 Q&A Instant Download Pdf
1. Which of the following systems is classified as a limited energy system?
A. 480V motor control circuit
B. 277V lighting circuit
C. Fire alarm signaling circuit
D. Medium-voltage distribution feeder
C. Fire alarm signaling circuit
Limited energy systems operate at lower voltages and power levels designed
to reduce shock and fire hazards. Fire alarm signaling circuits are commonly
classified as limited energy systems because they typically operate at low
voltage and current levels.
2. The primary purpose of a transformer in a low-voltage system is to:
A. Increase current flow only
B. Change voltage levels
C. Prevent grounding
D. Eliminate resistance
B. Change voltage levels
Transformers are electrical devices used to step voltage up or down through
electromagnetic induction. In limited energy systems, transformers commonly
,reduce standard building voltage to safer operating voltages such as 24V or
12V.
3. Which NEC article primarily governs fire alarm systems?
A. Article 250
B. Article 300
C. Article 760
D. Article 430
C. Article 760
NEC Article 760 covers installation requirements for fire alarm systems,
including wiring methods, power supplies, circuit separation, and equipment
installation standards.
4. Which NEC article covers Class 2 and Class 3 circuits?
A. Article 725
B. Article 770
C. Article 800
D. Article 820
A. Article 725
NEC Article 725 governs Class 1, Class 2, and Class 3 remote-control and
signaling circuits. Class 2 and Class 3 circuits are power-limited and operate
at lower energy levels.
5. A technician is installing a 24-V control circuit in a commercial building. The
circuit is supplied by a listed Class 2 power source. The technician wants to
route the conductors in the same raceway as 120-V branch-circuit conductors.
What is the primary code concern?
A. The Class 2 circuit must always be installed underground.
B. The 24-V circuit must be converted to a Class 1 circuit.
C. The conductors may require separation from the power conductors unless
the applicable NEC conditions for combining them are satisfied.
,D. The 120-V circuit must be reduced to 24 V.
C. The conductors may require separation from the power conductors unless
the applicable NEC conditions for combining them are satisfied.
Limited-energy conductors cannot simply be placed with higher-voltage
power conductors without satisfying the applicable separation and insulation
requirements. The classification of the circuit and the wiring method
determine what combinations are permitted.
6. A fire alarm technician is troubleshooting a notification circuit. The
measured resistance across the circuit is substantially higher than expected,
and several notification appliances are not operating. What is the most likely
problem?
A. A short circuit across the conductors
B. An open or high-resistance connection
C. Excessive grounding electrode resistance
D. An oversized transformer
B. An open or high-resistance connection
An open or high-resistance connection increases circuit resistance and can
prevent sufficient current from reaching downstream devices. A direct short
would normally produce a very low resistance.
7. A 24-V transformer supplies a control circuit drawing 2 A. Ignoring losses,
what is the approximate apparent power required from the transformer?
A. 12 VA
B. 24 VA
C. 48 VA
D. 96 VA
C. 48 VA
Using VA = V × A, 24V × 2A = 48VA.
, 8. A technician measures 24 V at the power supply but only 18 V at the
farthest control device under load. Which condition should be investigated
first?
A. Excessive voltage drop
B. Excessive grounding electrode resistance
C. Incorrect frequency
D. Excessive conductor insulation thickness
A. Excessive voltage drop
The six-volt difference under load strongly indicates voltage drop caused by
conductor resistance, excessive conductor length, inadequate conductor size,
or a poor connection.
9. A Class 2 circuit is extended through several junction boxes. Which
installation practice is most appropriate?
A. Leave all conductors unsupported between boxes.
B. Maintain proper conductor support and protect conductors from physical
damage.
C. Use ordinary extension cords permanently.
D. Remove all box covers after inspection.
B. Maintain proper conductor support and protect conductors from physical
damage.
Limited-energy wiring is still required to be installed in a workmanship-like
manner, with appropriate support and protection.
10. A technician is terminating a twisted-pair data cable. The cable's pairs are
untwisted several inches farther than necessary before termination. What is
the principal concern?
A. Increased conductor ampacity
B. Reduced electromagnetic performance and possible increased crosstalk
C. Increased insulation voltage rating
