Hawaii ES Supervising Electrician Exam Newest
(2026 Update) Actual Practice Questions – Set
100 Most Common Exam Questions And
Answers In Details 100% Verified Exam
1. A 240V single-phase load draws 18A. What is the power in watts?
A. 2,160 W
B. 3,240 W
C. 4,320 W
D. 5,400 W
✔ Correct Answer: B. 3,240 W
Rationale: Power = Voltage × Current = 240 × 18 = 3,240 watts.
2. What is the minimum grounding electrode conductor size for a 200A service
with copper conductors?
A. #8 AWG
B. #6 AWG
C. #4 AWG
D. #2 AWG
✔ Correct Answer: B. #6 AWG
Rationale: NEC sizing for typical 200A service grounding electrode
conductors allows #6 copper in most standard conditions.
3. A circuit has 12Ω resistance and 120V applied. What is the current?
A. 5A
B. 10A
C. 15A
D. 20A
✔ Correct Answer: B. 10A
Rationale: I = V ÷ R = 120 ÷ 12 = 10A.
,4. Which device protects against ground-fault current leakage in wet
locations?
A. AFCI
B. GFCI
C. Fuse
D. Thermal relay
✔ Correct Answer: B. GFCI
Rationale: GFCI devices trip when detecting ground-fault leakage,
especially in wet environments.
5. What is the primary purpose of a main bonding jumper?
A. Increase voltage stability
B. Connect neutral to ground at service equipment
C. Limit fault current
D. Reduce harmonics
✔ Correct Answer: B. Connect neutral to ground at service equipment
Rationale: The main bonding jumper establishes the grounded conductor
connection at service equipment only.
6. A 3-phase system measures 480V line-to-line. What is the phase voltage
(wye system)?
A. 208V
B. 240V
C. 277V
D. 480V
✔ Correct Answer: C. 277V
Rationale: Phase voltage = Line voltage ÷ √3 = 480 ÷ 1.732 ≈ 277V.
7. What is the maximum voltage drop recommended for branch circuits?
A. 1%
B. 3%
C. 5%
D. 10%
✔ Correct Answer: B. 3%
, Rationale: NEC recommended design limit is 3% for branch circuits for
efficiency.
8. A transformer steps down 480V to 120V. What type is it?
A. Step-up transformer
B. Isolation transformer
C. Step-down transformer
D. Auto transformer
✔ Correct Answer: C. Step-down transformer
Rationale: Voltage is reduced from higher to lower level.
9. Which conductor is typically considered the grounded conductor?
A. Phase conductor
B. Neutral conductor
C. Equipment grounding conductor
D. Bonding jumper
✔ Correct Answer: B. Neutral conductor
Rationale: The neutral carries current and is intentionally grounded at
service equipment.
10.What is the purpose of an AFCI breaker?
A. Prevent overloads only
B. Detect arc faults and disconnect circuit
C. Increase voltage stability
D. Reduce resistance
✔ Correct Answer: B. Detect arc faults and disconnect circuit
Rationale: AFCIs protect against electrical fires caused by arcing faults.
11.A 20A circuit operates at 120V continuously. What is the maximum
allowable load?
A. 12A
B. 16A
C. 18A
D. 20A
(2026 Update) Actual Practice Questions – Set
100 Most Common Exam Questions And
Answers In Details 100% Verified Exam
1. A 240V single-phase load draws 18A. What is the power in watts?
A. 2,160 W
B. 3,240 W
C. 4,320 W
D. 5,400 W
✔ Correct Answer: B. 3,240 W
Rationale: Power = Voltage × Current = 240 × 18 = 3,240 watts.
2. What is the minimum grounding electrode conductor size for a 200A service
with copper conductors?
A. #8 AWG
B. #6 AWG
C. #4 AWG
D. #2 AWG
✔ Correct Answer: B. #6 AWG
Rationale: NEC sizing for typical 200A service grounding electrode
conductors allows #6 copper in most standard conditions.
3. A circuit has 12Ω resistance and 120V applied. What is the current?
A. 5A
B. 10A
C. 15A
D. 20A
✔ Correct Answer: B. 10A
Rationale: I = V ÷ R = 120 ÷ 12 = 10A.
,4. Which device protects against ground-fault current leakage in wet
locations?
A. AFCI
B. GFCI
C. Fuse
D. Thermal relay
✔ Correct Answer: B. GFCI
Rationale: GFCI devices trip when detecting ground-fault leakage,
especially in wet environments.
5. What is the primary purpose of a main bonding jumper?
A. Increase voltage stability
B. Connect neutral to ground at service equipment
C. Limit fault current
D. Reduce harmonics
✔ Correct Answer: B. Connect neutral to ground at service equipment
Rationale: The main bonding jumper establishes the grounded conductor
connection at service equipment only.
6. A 3-phase system measures 480V line-to-line. What is the phase voltage
(wye system)?
A. 208V
B. 240V
C. 277V
D. 480V
✔ Correct Answer: C. 277V
Rationale: Phase voltage = Line voltage ÷ √3 = 480 ÷ 1.732 ≈ 277V.
7. What is the maximum voltage drop recommended for branch circuits?
A. 1%
B. 3%
C. 5%
D. 10%
✔ Correct Answer: B. 3%
, Rationale: NEC recommended design limit is 3% for branch circuits for
efficiency.
8. A transformer steps down 480V to 120V. What type is it?
A. Step-up transformer
B. Isolation transformer
C. Step-down transformer
D. Auto transformer
✔ Correct Answer: C. Step-down transformer
Rationale: Voltage is reduced from higher to lower level.
9. Which conductor is typically considered the grounded conductor?
A. Phase conductor
B. Neutral conductor
C. Equipment grounding conductor
D. Bonding jumper
✔ Correct Answer: B. Neutral conductor
Rationale: The neutral carries current and is intentionally grounded at
service equipment.
10.What is the purpose of an AFCI breaker?
A. Prevent overloads only
B. Detect arc faults and disconnect circuit
C. Increase voltage stability
D. Reduce resistance
✔ Correct Answer: B. Detect arc faults and disconnect circuit
Rationale: AFCIs protect against electrical fires caused by arcing faults.
11.A 20A circuit operates at 120V continuously. What is the maximum
allowable load?
A. 12A
B. 16A
C. 18A
D. 20A
