NCCER Electrical Level 3 Certification Exam
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
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1. Which of the following is the primary purpose of a transformer?
a) Convert AC to DC
b) Change voltage levels
c) Store electrical energy
d) Protect circuits from overload
Transformers are designed to increase or decrease voltage levels
while maintaining the same frequency.
2. A three-phase, four-wire wye system has a line voltage of 480 V.
What is the phase voltage?
a) 480 V
b) 416 V
c) 277 V
d) 240 V
Phase voltage in a wye system is line voltage divided by √3.
3. In an AC circuit, the current leads the voltage by 90 degrees. This
indicates the circuit is:
a) Resistive
b) Capacitive
c) Inductive
, d) Short-circuited
In a purely capacitive circuit, current leads voltage by 90 degrees.
4. Which of the following conductors has the highest resistivity?
a) Copper
b) Aluminum
c) Nichrome
d) Silver
Nichrome is a high-resistance alloy commonly used in heating
elements.
5. The National Electrical Code (NEC) requires ground-fault
protection for which type of circuits?
a) Lighting circuits only
b) Personnel protection on certain feeders and branch circuits
c) Only low-voltage circuits
d) Only motors
GFCI protection is required to protect personnel from shock on
specified circuits.
6. What is the primary function of a motor starter?
a) Increase voltage
b) Control the starting and stopping of a motor safely
c) Convert AC to DC
d) Reduce friction in the motor
Motor starters provide safe starting, stopping, and overload
protection for motors.
7. Which type of motor is commonly used for variable speed
applications in industrial settings?
a) Synchronous motor
, b) AC induction motor with VFD
c) Shunt DC motor
d) Series DC motor
Variable frequency drives (VFDs) allow AC induction motors to run
at variable speeds.
8. What is the voltage drop across a 50-meter copper conductor
carrying 20 A with a resistance of 0.2 Ω?
a) 2 V
b) 10 V
c) 4 V
d) 20 V
Voltage drop = Current × Resistance = 20 A × 0.2 Ω = 4 V.
9. The function of a surge protector is to:
a) Convert AC to DC
b) Protect equipment from voltage spikes
c) Limit current flow in normal operation
d) Provide backup power
Surge protectors divert or absorb voltage spikes to protect
sensitive equipment.
10. Which of the following is true regarding series circuits?
a) Voltage is the same across all components
b) Current is the same through all components
c) Total resistance decreases as more resistors are added
d) Power is the same across all components
In a series circuit, the same current flows through every
component.
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 transformer?
a) Convert AC to DC
b) Change voltage levels
c) Store electrical energy
d) Protect circuits from overload
Transformers are designed to increase or decrease voltage levels
while maintaining the same frequency.
2. A three-phase, four-wire wye system has a line voltage of 480 V.
What is the phase voltage?
a) 480 V
b) 416 V
c) 277 V
d) 240 V
Phase voltage in a wye system is line voltage divided by √3.
3. In an AC circuit, the current leads the voltage by 90 degrees. This
indicates the circuit is:
a) Resistive
b) Capacitive
c) Inductive
, d) Short-circuited
In a purely capacitive circuit, current leads voltage by 90 degrees.
4. Which of the following conductors has the highest resistivity?
a) Copper
b) Aluminum
c) Nichrome
d) Silver
Nichrome is a high-resistance alloy commonly used in heating
elements.
5. The National Electrical Code (NEC) requires ground-fault
protection for which type of circuits?
a) Lighting circuits only
b) Personnel protection on certain feeders and branch circuits
c) Only low-voltage circuits
d) Only motors
GFCI protection is required to protect personnel from shock on
specified circuits.
6. What is the primary function of a motor starter?
a) Increase voltage
b) Control the starting and stopping of a motor safely
c) Convert AC to DC
d) Reduce friction in the motor
Motor starters provide safe starting, stopping, and overload
protection for motors.
7. Which type of motor is commonly used for variable speed
applications in industrial settings?
a) Synchronous motor
, b) AC induction motor with VFD
c) Shunt DC motor
d) Series DC motor
Variable frequency drives (VFDs) allow AC induction motors to run
at variable speeds.
8. What is the voltage drop across a 50-meter copper conductor
carrying 20 A with a resistance of 0.2 Ω?
a) 2 V
b) 10 V
c) 4 V
d) 20 V
Voltage drop = Current × Resistance = 20 A × 0.2 Ω = 4 V.
9. The function of a surge protector is to:
a) Convert AC to DC
b) Protect equipment from voltage spikes
c) Limit current flow in normal operation
d) Provide backup power
Surge protectors divert or absorb voltage spikes to protect
sensitive equipment.
10. Which of the following is true regarding series circuits?
a) Voltage is the same across all components
b) Current is the same through all components
c) Total resistance decreases as more resistors are added
d) Power is the same across all components
In a series circuit, the same current flows through every
component.
