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Hawaii Supervising Electrician (ES)
Examination Advanced 100-Question
Practice Exam 2026 | Questions &
Answers with Detailed Rationales |
Complete Exam Prep & Study Guide
1. A supervising electrician is reviewing a 120/208-volt, 3-phase, 4-wire
system. A significant amount of nonlinear electronic equipment will be
connected to the system. Which conductor is most likely to require special
consideration because of harmonic currents?
A. Equipment grounding conductor
B. Grounding electrode conductor
C. Neutral conductor
D. Bonding jumper
Answer: C. Neutral conductor
Rationale: Harmonic currents generated by nonlinear loads can accumulate in
the neutral of a 3-phase, 4-wire system rather than cancel as fundamental-
frequency currents do. The supervising electrician must evaluate the neutral
conductor for the expected harmonic loading.
2. A feeder supplies a continuous load of 48 amperes. What minimum
ampacity is generally required for the ungrounded conductors before
applying any other adjustment or correction factors?
,A. 48 A
B. 50 A
C. 60 A
D. 75 A
Answer: C. 60 A
Rationale: A continuous load is generally calculated at 125 percent. Thus, 48 ×
1.25 = 60 amperes.
3. A supervising electrician discovers that several branch circuits have been
installed without proper equipment grounding conductors. What is the
primary safety concern?
A. Excessive voltage drop
B. Increased fault-clearing impedance
C. Excessive neutral current
D. Reduced power factor
Answer: B. Increased fault-clearing impedance
Rationale: The equipment grounding path provides a low-impedance route for
fault current so protective devices can operate promptly. An inadequate
grounding path can prevent timely operation of the overcurrent device.
4. A 480Y/277-volt system has a line-to-line fault current of 22 kA available at
a panelboard. The panelboard is marked with an SCCR of 10 kA. What is the
supervising electrician's primary concern?
A. Conductor color
B. Panelboard interrupting capability
C. Neutral conductor size
D. Lighting load calculation
Answer: B. Panelboard interrupting capability
,Rationale: Equipment must have an adequate short-circuit current rating or
interrupting rating for the available fault current at its installation point. A 10-
kA rating is inadequate where the available fault current exceeds that rating.
5. When selecting an overcurrent protective device for a motor branch circuit,
which characteristic is especially important during motor starting?
A. Motor inrush current
B. Lighting demand factor
C. Neutral current
D. Grounding electrode resistance
Answer: A. Motor inrush current
Rationale: Motors can draw substantially higher current during starting than
during normal operation. The branch-circuit overcurrent protection must be
selected so that normal starting current does not cause nuisance tripping while
still providing required protection.
6. A motor has a nameplate full-load current of 34 amperes. The supervising
electrician is determining the conductor ampacity for the motor branch
circuit. Which value is generally used as the starting point for conductor
sizing?
A. Actual measured running current only
B. Motor nameplate current only in every case
C. The applicable code motor full-load-current value
D. Locked-rotor current
Answer: C. The applicable code motor full-load-current value
Rationale: Motor conductor sizing is generally based on the applicable code
motor full-load-current tables or requirements rather than simply using
measured operating current or locked-rotor current.
, 7. A service has multiple grounding electrode types available at a building.
What is the general requirement when more than one grounding electrode
is present?
A. Only the electrode with the lowest resistance is used
B. Each qualifying electrode must be connected as required
C. Electrodes must remain electrically isolated
D. Only the metal water pipe may be used
Answer: B. Each qualifying electrode must be connected as required
Rationale: Where multiple grounding electrodes are present and required, they
generally form part of the grounding electrode system and must be bonded
together in accordance with applicable requirements.
8. A supervising electrician is inspecting a feeder installed in a raceway. The
raceway contains conductors for several circuits. What factor must be
evaluated when determining conductor ampacity?
A. Only conductor insulation color
B. Number of current-carrying conductors
C. Length of the raceway only
D. Number of junction boxes
Answer: B. Number of current-carrying conductors
Rationale: More than three current-carrying conductors in a raceway, cable, or
enclosure can require ampacity adjustment. The applicable adjustment and
correction rules must be evaluated.
9. A voltage-drop calculation indicates that a long branch circuit will
experience excessive voltage drop even though the conductors meet
minimum ampacity requirements. What is the best corrective approach?
A. Increase the overcurrent-device rating
B. Increase conductor size
Hawaii Supervising Electrician (ES)
Examination Advanced 100-Question
Practice Exam 2026 | Questions &
Answers with Detailed Rationales |
Complete Exam Prep & Study Guide
1. A supervising electrician is reviewing a 120/208-volt, 3-phase, 4-wire
system. A significant amount of nonlinear electronic equipment will be
connected to the system. Which conductor is most likely to require special
consideration because of harmonic currents?
A. Equipment grounding conductor
B. Grounding electrode conductor
C. Neutral conductor
D. Bonding jumper
Answer: C. Neutral conductor
Rationale: Harmonic currents generated by nonlinear loads can accumulate in
the neutral of a 3-phase, 4-wire system rather than cancel as fundamental-
frequency currents do. The supervising electrician must evaluate the neutral
conductor for the expected harmonic loading.
2. A feeder supplies a continuous load of 48 amperes. What minimum
ampacity is generally required for the ungrounded conductors before
applying any other adjustment or correction factors?
,A. 48 A
B. 50 A
C. 60 A
D. 75 A
Answer: C. 60 A
Rationale: A continuous load is generally calculated at 125 percent. Thus, 48 ×
1.25 = 60 amperes.
3. A supervising electrician discovers that several branch circuits have been
installed without proper equipment grounding conductors. What is the
primary safety concern?
A. Excessive voltage drop
B. Increased fault-clearing impedance
C. Excessive neutral current
D. Reduced power factor
Answer: B. Increased fault-clearing impedance
Rationale: The equipment grounding path provides a low-impedance route for
fault current so protective devices can operate promptly. An inadequate
grounding path can prevent timely operation of the overcurrent device.
4. A 480Y/277-volt system has a line-to-line fault current of 22 kA available at
a panelboard. The panelboard is marked with an SCCR of 10 kA. What is the
supervising electrician's primary concern?
A. Conductor color
B. Panelboard interrupting capability
C. Neutral conductor size
D. Lighting load calculation
Answer: B. Panelboard interrupting capability
,Rationale: Equipment must have an adequate short-circuit current rating or
interrupting rating for the available fault current at its installation point. A 10-
kA rating is inadequate where the available fault current exceeds that rating.
5. When selecting an overcurrent protective device for a motor branch circuit,
which characteristic is especially important during motor starting?
A. Motor inrush current
B. Lighting demand factor
C. Neutral current
D. Grounding electrode resistance
Answer: A. Motor inrush current
Rationale: Motors can draw substantially higher current during starting than
during normal operation. The branch-circuit overcurrent protection must be
selected so that normal starting current does not cause nuisance tripping while
still providing required protection.
6. A motor has a nameplate full-load current of 34 amperes. The supervising
electrician is determining the conductor ampacity for the motor branch
circuit. Which value is generally used as the starting point for conductor
sizing?
A. Actual measured running current only
B. Motor nameplate current only in every case
C. The applicable code motor full-load-current value
D. Locked-rotor current
Answer: C. The applicable code motor full-load-current value
Rationale: Motor conductor sizing is generally based on the applicable code
motor full-load-current tables or requirements rather than simply using
measured operating current or locked-rotor current.
, 7. A service has multiple grounding electrode types available at a building.
What is the general requirement when more than one grounding electrode
is present?
A. Only the electrode with the lowest resistance is used
B. Each qualifying electrode must be connected as required
C. Electrodes must remain electrically isolated
D. Only the metal water pipe may be used
Answer: B. Each qualifying electrode must be connected as required
Rationale: Where multiple grounding electrodes are present and required, they
generally form part of the grounding electrode system and must be bonded
together in accordance with applicable requirements.
8. A supervising electrician is inspecting a feeder installed in a raceway. The
raceway contains conductors for several circuits. What factor must be
evaluated when determining conductor ampacity?
A. Only conductor insulation color
B. Number of current-carrying conductors
C. Length of the raceway only
D. Number of junction boxes
Answer: B. Number of current-carrying conductors
Rationale: More than three current-carrying conductors in a raceway, cable, or
enclosure can require ampacity adjustment. The applicable adjustment and
correction rules must be evaluated.
9. A voltage-drop calculation indicates that a long branch circuit will
experience excessive voltage drop even though the conductors meet
minimum ampacity requirements. What is the best corrective approach?
A. Increase the overcurrent-device rating
B. Increase conductor size
