California PE Electrical Practice Exam
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the RMS value of a sinusoidal voltage with a peak value of 170
V?
A. 85 V
B. 120 V
C. 120.2 V
D. 170 V
Rationale: The RMS value is Vpeak/2=170/2=120.2V_{peak} /
\sqrt{2} = 170 / \sqrt{2} = 120.2Vpeak/2=170/2=120.2 V.
2. A 3-phase system delivers 100 kW at 0.8 power factor lagging. What is
the reactive power (Q)?
A. 60 kVAR
B. 75 kVAR
C. 75 kVAR lagging
D. 80 kVAR
Rationale: Q=P⋅tan(cos−1(0.8))=100⋅0.75=75 kVARQ = P \cdot
\tan(\cos^{-1}(0.8)) = 100 \cdot 0.75 = 75 \text{
kVAR}Q=P⋅tan(cos−1(0.8))=100⋅0.75=75 kVAR.
,3. What is the impedance of a circuit with R = 3 ohms and X = 4 ohms?
A. 5 ohms
B. 5 Ω
C. 7 ohms
D. 1 ohm
Rationale: Impedance Z=R2+X2=32+42=5Z = \sqrt{R^2 + X^2} =
\sqrt{3^2 + 4^2} = 5Z=R2+X2=32+42=5 ohms.
4. A circuit breaker is rated at 20 A. What is the maximum continuous
current per NEC?
A. 20 A
B. 18 A
C. 16 A
D. 22 A
Rationale: NEC requires derating to 80% for continuous loads:
20⋅0.8=1620 \cdot 0.8 = 1620⋅0.8=16 A.
5. What is the total resistance of three 10-ohm resistors in parallel?
A. 10 ohms
B. 5 ohms
C. 3.33 ohms
D. 30 ohms
Rationale: Req=1/(1/10+1/10+1/10)=3.33R_{eq} = 1 / (1/10 + 1/10 +
1/10) = 3.33Req=1/(1/10+1/10+1/10)=3.33 ohms.
6. A transformer with 4:1 turns ratio steps down 480 V. What is the
secondary voltage?
A. 120 V
B. 120 V
C. 240 V
D. 12 V
, Rationale: Vsecondary=480/4=120V_{secondary} = =
120Vsecondary=480/4=120 V.
7. The power factor of a purely resistive circuit is:
A. 0
B. 1
C. 0.5
D. Cannot be determined
Rationale: For resistive loads, voltage and current are in phase, PF =
1.
8. Which of the following is an acceptable grounding method per NEC?
A. PVC conduit
B. Ground rod
C. EMT not bonded
D. Plastic water pipe
Rationale: Ground rods are approved grounding electrodes.
9. What is the effect of adding capacitors to an inductive load?
A. Increases power factor
B. Reduces line losses
C. Both A and B
D. Increases reactive power
Rationale: Capacitors cancel inductive VARs, improving PF and
reducing I²R losses.
10. What does a time-current curve for a circuit breaker show?
A. Energy usage over time
B. Trip time vs. fault current
C. Efficiency curve
D. Arc flash levels
Rationale: It shows how long a breaker takes to trip at varying fault
levels.
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the RMS value of a sinusoidal voltage with a peak value of 170
V?
A. 85 V
B. 120 V
C. 120.2 V
D. 170 V
Rationale: The RMS value is Vpeak/2=170/2=120.2V_{peak} /
\sqrt{2} = 170 / \sqrt{2} = 120.2Vpeak/2=170/2=120.2 V.
2. A 3-phase system delivers 100 kW at 0.8 power factor lagging. What is
the reactive power (Q)?
A. 60 kVAR
B. 75 kVAR
C. 75 kVAR lagging
D. 80 kVAR
Rationale: Q=P⋅tan(cos−1(0.8))=100⋅0.75=75 kVARQ = P \cdot
\tan(\cos^{-1}(0.8)) = 100 \cdot 0.75 = 75 \text{
kVAR}Q=P⋅tan(cos−1(0.8))=100⋅0.75=75 kVAR.
,3. What is the impedance of a circuit with R = 3 ohms and X = 4 ohms?
A. 5 ohms
B. 5 Ω
C. 7 ohms
D. 1 ohm
Rationale: Impedance Z=R2+X2=32+42=5Z = \sqrt{R^2 + X^2} =
\sqrt{3^2 + 4^2} = 5Z=R2+X2=32+42=5 ohms.
4. A circuit breaker is rated at 20 A. What is the maximum continuous
current per NEC?
A. 20 A
B. 18 A
C. 16 A
D. 22 A
Rationale: NEC requires derating to 80% for continuous loads:
20⋅0.8=1620 \cdot 0.8 = 1620⋅0.8=16 A.
5. What is the total resistance of three 10-ohm resistors in parallel?
A. 10 ohms
B. 5 ohms
C. 3.33 ohms
D. 30 ohms
Rationale: Req=1/(1/10+1/10+1/10)=3.33R_{eq} = 1 / (1/10 + 1/10 +
1/10) = 3.33Req=1/(1/10+1/10+1/10)=3.33 ohms.
6. A transformer with 4:1 turns ratio steps down 480 V. What is the
secondary voltage?
A. 120 V
B. 120 V
C. 240 V
D. 12 V
, Rationale: Vsecondary=480/4=120V_{secondary} = =
120Vsecondary=480/4=120 V.
7. The power factor of a purely resistive circuit is:
A. 0
B. 1
C. 0.5
D. Cannot be determined
Rationale: For resistive loads, voltage and current are in phase, PF =
1.
8. Which of the following is an acceptable grounding method per NEC?
A. PVC conduit
B. Ground rod
C. EMT not bonded
D. Plastic water pipe
Rationale: Ground rods are approved grounding electrodes.
9. What is the effect of adding capacitors to an inductive load?
A. Increases power factor
B. Reduces line losses
C. Both A and B
D. Increases reactive power
Rationale: Capacitors cancel inductive VARs, improving PF and
reducing I²R losses.
10. What does a time-current curve for a circuit breaker show?
A. Energy usage over time
B. Trip time vs. fault current
C. Efficiency curve
D. Arc flash levels
Rationale: It shows how long a breaker takes to trip at varying fault
levels.
