ELECTRICAL SYSTEM REVIEW
EXAMINATION WITH ACTUAL QUESTIONS
AND VERIFIED ANSWERS, PLUS
EXPLAINED RATIONALES/EXPERT
VERIFIED FOR GUARANTEED 100% PASS
2026/LATEST UPDATE/INSTANT
DOWNLOAD PDF
1. During a review of an electrical distribution system, an inspector
discovers that the calculated continuous load on a feeder is 80 A and
the noncontinuous load is 40 A. Assuming standard sizing rules
apply and no special derating or adjustment factors are required,
what minimum ampacity should the feeder conductor be designed to
carry?
A. 100 A
B. 120 A
C. 130 A
D. 160 A
Answer: B. 120 A
Rationale: The continuous load must generally be multiplied by 125%
and then added to the noncontinuous load. Thus, 80 A × 1.25 = 100 A,
and 100 A + 40 A = 140 A. Therefore, among the listed choices, none
exactly represents the calculation. A properly designed feeder would
require at least 140 A ampacity, making this question technically
inconsistent. The correct engineering conclusion is 140 A, not 120 A.
1
,2. A three-phase, 480-V motor has a full-load current of 28 A. When
reviewing the motor branch-circuit conductors, which principle is
most important?
A. Size conductors only according to the overcurrent protective device
B. Size conductors according to the motor's full-load current and
applicable motor-conductor requirements
C. Size conductors exactly equal to the motor nameplate horsepower
D. Use the same conductor size as the service entrance conductors
Answer: B. Size conductors according to the motor's full-load
current and applicable motor-conductor requirements
Rationale: Motor branch-circuit conductor sizing is based on the
applicable motor full-load current and required percentage increase,
rather than simply matching the overcurrent device or service
conductor size. Motor circuits have specific requirements because
starting current and operating characteristics differ from ordinary
resistive loads.
3. During a panelboard review, an electrical reviewer observes that
the panel has a listed bus rating of 225 A, while the proposed main
overcurrent device is 250 A. What is the primary concern?
A. The panel is automatically acceptable because the feeder conductors
are 250 A
B. The panelboard bus may be subjected to current exceeding its listed
rating
C. The panel must have a 100 A main breaker
D. The panel voltage must be reduced
Answer: B. The panelboard bus may be subjected to current
exceeding its listed rating
2
,Rationale: Electrical equipment must be operated within its listed
ratings unless a specific permitted exception applies. A 250-A
protective device supplying a panel with a 225-A bus rating raises a
fundamental equipment-rating concern. The reviewer should verify
the listing, permitted applications, and applicable overcurrent-
protection requirements before approval.
4. A building has a 120/208-V, three-phase, four-wire electrical
service. Which voltage would normally be measured between two
ungrounded phase conductors?
A. 120 V
B. 173 V
C. 208 V
D. 240 V
Answer: C. 208 V
Rationale: In a typical 120/208-V wye system, each phase conductor is
approximately 120 V to the neutral, while the voltage between two
phase conductors is 208 V. The relationship is approximately 120 × √3
= 208 V.
5. An electrical system review identifies a 120-V branch circuit
supplying several receptacles in a wet location. Which protective
measure is generally most important for personnel protection?
A. Increasing conductor size
B. Installing surge protection only
C. Providing appropriate ground-fault protection
D. Increasing the circuit voltage
Answer: C. Providing appropriate ground-fault protection
3
, Rationale: Ground-fault protection is intended to reduce the risk of
electric shock when current unintentionally travels through a person
or other conductive path to ground. Wet locations increase the
potential severity of electrical shock, making appropriate ground-fault
protection especially important.
6. A reviewer is evaluating the available fault current at a new
switchboard. Why is this calculation important?
A. It determines the building's lighting levels
B. It establishes whether equipment has adequate short-circuit ratings
C. It determines the number of receptacles required
D. It establishes the required ceiling height
Answer: B. It establishes whether equipment has adequate short-
circuit ratings
Rationale: Available fault current can be extremely high near
electrical sources. Electrical equipment must have appropriate short-
circuit current ratings so that it can withstand or interrupt prospective
fault currents without catastrophic failure.
7. A transformer has a 480-V primary and a 208Y/120-V secondary.
What is the primary purpose of the transformer in this application?
A. To increase the secondary voltage above 480 V
B. To convert electrical energy to mechanical energy
C. To reduce voltage and provide the required secondary distribution
system
D. To eliminate all electrical faults
Answer: C. To reduce voltage and provide the required secondary
distribution system
4
EXAMINATION WITH ACTUAL QUESTIONS
AND VERIFIED ANSWERS, PLUS
EXPLAINED RATIONALES/EXPERT
VERIFIED FOR GUARANTEED 100% PASS
2026/LATEST UPDATE/INSTANT
DOWNLOAD PDF
1. During a review of an electrical distribution system, an inspector
discovers that the calculated continuous load on a feeder is 80 A and
the noncontinuous load is 40 A. Assuming standard sizing rules
apply and no special derating or adjustment factors are required,
what minimum ampacity should the feeder conductor be designed to
carry?
A. 100 A
B. 120 A
C. 130 A
D. 160 A
Answer: B. 120 A
Rationale: The continuous load must generally be multiplied by 125%
and then added to the noncontinuous load. Thus, 80 A × 1.25 = 100 A,
and 100 A + 40 A = 140 A. Therefore, among the listed choices, none
exactly represents the calculation. A properly designed feeder would
require at least 140 A ampacity, making this question technically
inconsistent. The correct engineering conclusion is 140 A, not 120 A.
1
,2. A three-phase, 480-V motor has a full-load current of 28 A. When
reviewing the motor branch-circuit conductors, which principle is
most important?
A. Size conductors only according to the overcurrent protective device
B. Size conductors according to the motor's full-load current and
applicable motor-conductor requirements
C. Size conductors exactly equal to the motor nameplate horsepower
D. Use the same conductor size as the service entrance conductors
Answer: B. Size conductors according to the motor's full-load
current and applicable motor-conductor requirements
Rationale: Motor branch-circuit conductor sizing is based on the
applicable motor full-load current and required percentage increase,
rather than simply matching the overcurrent device or service
conductor size. Motor circuits have specific requirements because
starting current and operating characteristics differ from ordinary
resistive loads.
3. During a panelboard review, an electrical reviewer observes that
the panel has a listed bus rating of 225 A, while the proposed main
overcurrent device is 250 A. What is the primary concern?
A. The panel is automatically acceptable because the feeder conductors
are 250 A
B. The panelboard bus may be subjected to current exceeding its listed
rating
C. The panel must have a 100 A main breaker
D. The panel voltage must be reduced
Answer: B. The panelboard bus may be subjected to current
exceeding its listed rating
2
,Rationale: Electrical equipment must be operated within its listed
ratings unless a specific permitted exception applies. A 250-A
protective device supplying a panel with a 225-A bus rating raises a
fundamental equipment-rating concern. The reviewer should verify
the listing, permitted applications, and applicable overcurrent-
protection requirements before approval.
4. A building has a 120/208-V, three-phase, four-wire electrical
service. Which voltage would normally be measured between two
ungrounded phase conductors?
A. 120 V
B. 173 V
C. 208 V
D. 240 V
Answer: C. 208 V
Rationale: In a typical 120/208-V wye system, each phase conductor is
approximately 120 V to the neutral, while the voltage between two
phase conductors is 208 V. The relationship is approximately 120 × √3
= 208 V.
5. An electrical system review identifies a 120-V branch circuit
supplying several receptacles in a wet location. Which protective
measure is generally most important for personnel protection?
A. Increasing conductor size
B. Installing surge protection only
C. Providing appropriate ground-fault protection
D. Increasing the circuit voltage
Answer: C. Providing appropriate ground-fault protection
3
, Rationale: Ground-fault protection is intended to reduce the risk of
electric shock when current unintentionally travels through a person
or other conductive path to ground. Wet locations increase the
potential severity of electrical shock, making appropriate ground-fault
protection especially important.
6. A reviewer is evaluating the available fault current at a new
switchboard. Why is this calculation important?
A. It determines the building's lighting levels
B. It establishes whether equipment has adequate short-circuit ratings
C. It determines the number of receptacles required
D. It establishes the required ceiling height
Answer: B. It establishes whether equipment has adequate short-
circuit ratings
Rationale: Available fault current can be extremely high near
electrical sources. Electrical equipment must have appropriate short-
circuit current ratings so that it can withstand or interrupt prospective
fault currents without catastrophic failure.
7. A transformer has a 480-V primary and a 208Y/120-V secondary.
What is the primary purpose of the transformer in this application?
A. To increase the secondary voltage above 480 V
B. To convert electrical energy to mechanical energy
C. To reduce voltage and provide the required secondary distribution
system
D. To eliminate all electrical faults
Answer: C. To reduce voltage and provide the required secondary
distribution system
4
