Illinois Industrial Electrician Licensing
Examination Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. Which of the following is the primary purpose of a fuse in an electrical
circuit?
A. Increase voltage
B. Protect the circuit from overcurrent
C. Store electrical energy
D. Reduce resistance
Rationale: Fuses are designed to protect electrical circuits by breaking
the circuit if the current exceeds a safe level, preventing damage or
fire.
,2. What is the standard voltage for most industrial three-phase systems
in the U.S.?
A. 120V
B. 208V
C. 480V
D. 600V
Rationale: 480V is a common voltage for industrial three-phase
systems, suitable for heavy machinery.
3. In an AC circuit, what does the term “power factor” describe?
A. Resistance of the circuit
B. The phase difference between voltage and current
C. Voltage drop
D. Frequency stability
Rationale: Power factor is the cosine of the phase angle between
voltage and current, indicating how effectively electrical power is used.
4. Which type of motor is most commonly used in industrial variable
speed applications?
A. Synchronous motor
B. Shunt DC motor
C. Induction motor
D. Stepper motor
Rationale: Induction motors are widely used in industrial settings for
variable speed applications due to their robustness and simplicity.
,5. What is the purpose of a grounding conductor?
A. Increase voltage
B. Provide a path for fault current to reduce shock risk
C. Store energy
D. Increase current flow
Rationale: Grounding conductors safely carry fault current to the
earth, protecting equipment and personnel.
6. Which of the following is a common method of controlling an
industrial motor?
A. Single-pole switch
B. Motor starter with overload protection
C. Fuse only
D. Capacitor bank
Rationale: Motor starters provide control and overload protection,
ensuring safe operation of industrial motors.
7. According to the NEC, what is the maximum allowable voltage drop for
branch circuits?
A. 1%
B. 3%
C. 5%
D. 10%
Rationale: The NEC recommends a maximum of 5% voltage drop for
efficiency and proper operation of electrical devices.
, 8. What is the main advantage of a three-phase power system over a
single-phase system?
A. More efficient power delivery
B. Lower voltage
C. Simpler wiring
D. Less expensive
Rationale: Three-phase systems deliver power more efficiently and can
operate heavy machinery more effectively than single-phase systems.
9. Which instrument is used to measure current without breaking the
circuit?
A. Voltmeter
B. Clamp meter
C. Ohmmeter
D. Wattmeter
Rationale: Clamp meters can measure current by clamping around a
conductor, avoiding the need to disconnect the circuit.
10. What is the primary purpose of a contactor in industrial control
circuits?
A. Reduce voltage
B. Store energy
C. Switch high-current loads remotely
D. Measure resistance
Examination Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. Which of the following is the primary purpose of a fuse in an electrical
circuit?
A. Increase voltage
B. Protect the circuit from overcurrent
C. Store electrical energy
D. Reduce resistance
Rationale: Fuses are designed to protect electrical circuits by breaking
the circuit if the current exceeds a safe level, preventing damage or
fire.
,2. What is the standard voltage for most industrial three-phase systems
in the U.S.?
A. 120V
B. 208V
C. 480V
D. 600V
Rationale: 480V is a common voltage for industrial three-phase
systems, suitable for heavy machinery.
3. In an AC circuit, what does the term “power factor” describe?
A. Resistance of the circuit
B. The phase difference between voltage and current
C. Voltage drop
D. Frequency stability
Rationale: Power factor is the cosine of the phase angle between
voltage and current, indicating how effectively electrical power is used.
4. Which type of motor is most commonly used in industrial variable
speed applications?
A. Synchronous motor
B. Shunt DC motor
C. Induction motor
D. Stepper motor
Rationale: Induction motors are widely used in industrial settings for
variable speed applications due to their robustness and simplicity.
,5. What is the purpose of a grounding conductor?
A. Increase voltage
B. Provide a path for fault current to reduce shock risk
C. Store energy
D. Increase current flow
Rationale: Grounding conductors safely carry fault current to the
earth, protecting equipment and personnel.
6. Which of the following is a common method of controlling an
industrial motor?
A. Single-pole switch
B. Motor starter with overload protection
C. Fuse only
D. Capacitor bank
Rationale: Motor starters provide control and overload protection,
ensuring safe operation of industrial motors.
7. According to the NEC, what is the maximum allowable voltage drop for
branch circuits?
A. 1%
B. 3%
C. 5%
D. 10%
Rationale: The NEC recommends a maximum of 5% voltage drop for
efficiency and proper operation of electrical devices.
, 8. What is the main advantage of a three-phase power system over a
single-phase system?
A. More efficient power delivery
B. Lower voltage
C. Simpler wiring
D. Less expensive
Rationale: Three-phase systems deliver power more efficiently and can
operate heavy machinery more effectively than single-phase systems.
9. Which instrument is used to measure current without breaking the
circuit?
A. Voltmeter
B. Clamp meter
C. Ohmmeter
D. Wattmeter
Rationale: Clamp meters can measure current by clamping around a
conductor, avoiding the need to disconnect the circuit.
10. What is the primary purpose of a contactor in industrial control
circuits?
A. Reduce voltage
B. Store energy
C. Switch high-current loads remotely
D. Measure resistance
