Electrician License Exam (Journeyman / State) Updated 2026 | Comprehensive
Study Guide, Practice Exam Questions and Answers, Exam Prep Test Bank,
Electrical Theory Fundamentals, National Electrical Code (NEC) Review, Wiring
Methods and Installations, Circuit Analysis, Safety Standards, Troubleshooting
Techniques, and Detailed Revision Material for Licensing Success
Question 1: What is the primary purpose of the National Electrical Code (NEC)?
A. To enforce local building codes
B. To promote the safe installation of electrical wiring and equipment
C. To regulate the electrical utility industry
D. To provide architectural design standards
CORRECT ANSWER: B. To promote the safe installation of electrical wiring and
equipment
Rationale: The National Electrical Code (NEC) is a benchmark for the safe installation of
electrical wiring and equipment to protect people and property from electrical hazards .
While it is often adopted into law, its primary purpose is safety, not architectural or
utility regulation.
Question 2: Which unit is used to measure electrical current?
A. Volt
B. Ohm
C. Ampere
D. Watt
CORRECT ANSWER: C. Ampere
Rationale: The ampere is the standard unit of measurement for electrical current, which
is the rate of flow of electric charge . A volt measures electrical pressure, an ohm
measures resistance, and a watt measures power.
Question 3: In accordance with Ohm's Law, what is the formula for calculating
voltage?
A. V = I × R
B. V = I / R
C. V = P / I
D. V = R / I
CORRECT ANSWER: A. V = I × R
Rationale: Ohm's Law defines the fundamental relationship between voltage (V),
current (I), and resistance (R) in a circuit: Voltage is equal to the current multiplied by
the resistance .
Question 4: What is the standard color for a grounded neutral conductor in a
120/240V residential system?
,A. Green
B. Black
C. Red
D. White
CORRECT ANSWER: D. White
Rationale: The NEC requires the grounded neutral conductor to be identified by white or
gray insulation . Green is reserved for the equipment grounding conductor.
Question 5: A ground fault circuit interrupter (GFCI) is designed to protect people
from electric shock by:
A. Preventing power surges
B. Detecting an imbalance between the hot and neutral conductors
C. Interrupting power during an overload condition
D. Reducing the voltage to a safe level
CORRECT ANSWER: B. Detecting an imbalance between the hot and neutral
conductors
Rationale: A GFCI functions by monitoring the current flowing on the ungrounded (hot)
and grounded (neutral) conductors. If a difference (imbalance) is detected, it means
current is leaking through a person or other unintended path, and the GFCI trips to
prevent shock .
Question 6: What is the ampacity of a conductor?
A. The physical length of the conductor
B. The maximum current a conductor can carry continuously without exceeding its
temperature rating
C. The voltage drop across the conductor
D. The resistance of the conductor per foot
CORRECT ANSWER: B. The maximum current a conductor can carry continuously
without exceeding its temperature rating
Rationale: Ampacity is the maximum amount of electrical current a conductor can carry
before its temperature reaches a point that could damage its insulation or create a fire
hazard .
Question 7: What is the minimum number of disconnects permitted to be used to
disconnect all power to a building?
A. One
B. Two
C. Six
D. No limit
CORRECT ANSWER: C. Six
,Rationale: The NEC generally allows a maximum of six switches or circuit breakers to
serve as the main disconnecting means for a building, allowing a first responder to shut
off all power .
Question 8: In a motor circuit, a starter is primarily used to:
A. Increase the motor's speed
B. Protect against ground faults
C. Protect the motor from overloads
D. Convert AC to DC power
CORRECT ANSWER: C. Protect the motor from overloads
Rationale: A motor starter includes an overload protection device (heater elements)
that monitors the current drawn by the motor. If the current exceeds the rated value for a
specific time, the starter will open the circuit to prevent the motor from overheating and
being damaged .
Question 9: What is the minimum working space depth generally required in front
of an electrical panel rated 120/240V?
A. 2 feet
B. 2.5 feet
C. 3 feet
D. 4 feet
CORRECT ANSWER: C. 3 feet
Rationale: For equipment operating at 151 to 600 volts, the NEC requires a minimum
depth of 3 feet in the working space in front of the equipment to provide a safe
environment for maintenance and operation .
Question 10: A device that converts alternating current (AC) to direct current (DC) is
known as a:
A. Transformer
B. Generator
C. Rectifier
D. Inverter
CORRECT ANSWER: C. Rectifier
Rationale: A rectifier is an electrical device that converts alternating current (AC), which
periodically reverses direction, into direct current (DC), which flows in only one
direction .
Question 11: What is the primary function of conduit in an electrical installation?
A. To increase the circuit's ampacity
B. To provide a low-resistance path to ground
, C. To protect conductors from physical damage and serve as a raceway
D. To serve as the primary grounding electrode
CORRECT ANSWER: C. To protect conductors from physical damage and serve as a
raceway
Rationale: Conduit is a raceway that provides physical protection for the conductors it
encloses, shielding them from damage and environmental factors .
Question 12: Which instrument is used to measure the resistance of a circuit or
component?
A. Voltmeter
B. Ammeter
C. Megger
D. Ohmmeter
CORRECT ANSWER: D. Ohmmeter
Rationale: An ohmmeter is used to measure electrical resistance in ohms. It is
commonly found as a function on a multimeter . A megger measures high resistance,
such as insulation resistance.
Question 13: According to the NEC, for a continuous load, a branch circuit must be
sized at what percentage of the load?
A. 80%
B. 100%
C. 125%
D. 150%
CORRECT ANSWER: C. 125%
Rationale: The NEC requires that the branch circuit overcurrent device and conductors
be sized at 125% of the continuous load. This is to account for heat build-up and ensure
reliability .
Question 14: What is the standard frequency for AC power in the United States?
A. 50 Hz
B. 60 Hz
C. 120 Hz
D. 240 Hz
CORRECT ANSWER: B. 60 Hz
Rationale: The standard frequency for alternating current (AC) in North America is 60
Hertz (Hz), meaning the current changes direction 60 times per second .
Question 15: A "short circuit" is best described as:
Study Guide, Practice Exam Questions and Answers, Exam Prep Test Bank,
Electrical Theory Fundamentals, National Electrical Code (NEC) Review, Wiring
Methods and Installations, Circuit Analysis, Safety Standards, Troubleshooting
Techniques, and Detailed Revision Material for Licensing Success
Question 1: What is the primary purpose of the National Electrical Code (NEC)?
A. To enforce local building codes
B. To promote the safe installation of electrical wiring and equipment
C. To regulate the electrical utility industry
D. To provide architectural design standards
CORRECT ANSWER: B. To promote the safe installation of electrical wiring and
equipment
Rationale: The National Electrical Code (NEC) is a benchmark for the safe installation of
electrical wiring and equipment to protect people and property from electrical hazards .
While it is often adopted into law, its primary purpose is safety, not architectural or
utility regulation.
Question 2: Which unit is used to measure electrical current?
A. Volt
B. Ohm
C. Ampere
D. Watt
CORRECT ANSWER: C. Ampere
Rationale: The ampere is the standard unit of measurement for electrical current, which
is the rate of flow of electric charge . A volt measures electrical pressure, an ohm
measures resistance, and a watt measures power.
Question 3: In accordance with Ohm's Law, what is the formula for calculating
voltage?
A. V = I × R
B. V = I / R
C. V = P / I
D. V = R / I
CORRECT ANSWER: A. V = I × R
Rationale: Ohm's Law defines the fundamental relationship between voltage (V),
current (I), and resistance (R) in a circuit: Voltage is equal to the current multiplied by
the resistance .
Question 4: What is the standard color for a grounded neutral conductor in a
120/240V residential system?
,A. Green
B. Black
C. Red
D. White
CORRECT ANSWER: D. White
Rationale: The NEC requires the grounded neutral conductor to be identified by white or
gray insulation . Green is reserved for the equipment grounding conductor.
Question 5: A ground fault circuit interrupter (GFCI) is designed to protect people
from electric shock by:
A. Preventing power surges
B. Detecting an imbalance between the hot and neutral conductors
C. Interrupting power during an overload condition
D. Reducing the voltage to a safe level
CORRECT ANSWER: B. Detecting an imbalance between the hot and neutral
conductors
Rationale: A GFCI functions by monitoring the current flowing on the ungrounded (hot)
and grounded (neutral) conductors. If a difference (imbalance) is detected, it means
current is leaking through a person or other unintended path, and the GFCI trips to
prevent shock .
Question 6: What is the ampacity of a conductor?
A. The physical length of the conductor
B. The maximum current a conductor can carry continuously without exceeding its
temperature rating
C. The voltage drop across the conductor
D. The resistance of the conductor per foot
CORRECT ANSWER: B. The maximum current a conductor can carry continuously
without exceeding its temperature rating
Rationale: Ampacity is the maximum amount of electrical current a conductor can carry
before its temperature reaches a point that could damage its insulation or create a fire
hazard .
Question 7: What is the minimum number of disconnects permitted to be used to
disconnect all power to a building?
A. One
B. Two
C. Six
D. No limit
CORRECT ANSWER: C. Six
,Rationale: The NEC generally allows a maximum of six switches or circuit breakers to
serve as the main disconnecting means for a building, allowing a first responder to shut
off all power .
Question 8: In a motor circuit, a starter is primarily used to:
A. Increase the motor's speed
B. Protect against ground faults
C. Protect the motor from overloads
D. Convert AC to DC power
CORRECT ANSWER: C. Protect the motor from overloads
Rationale: A motor starter includes an overload protection device (heater elements)
that monitors the current drawn by the motor. If the current exceeds the rated value for a
specific time, the starter will open the circuit to prevent the motor from overheating and
being damaged .
Question 9: What is the minimum working space depth generally required in front
of an electrical panel rated 120/240V?
A. 2 feet
B. 2.5 feet
C. 3 feet
D. 4 feet
CORRECT ANSWER: C. 3 feet
Rationale: For equipment operating at 151 to 600 volts, the NEC requires a minimum
depth of 3 feet in the working space in front of the equipment to provide a safe
environment for maintenance and operation .
Question 10: A device that converts alternating current (AC) to direct current (DC) is
known as a:
A. Transformer
B. Generator
C. Rectifier
D. Inverter
CORRECT ANSWER: C. Rectifier
Rationale: A rectifier is an electrical device that converts alternating current (AC), which
periodically reverses direction, into direct current (DC), which flows in only one
direction .
Question 11: What is the primary function of conduit in an electrical installation?
A. To increase the circuit's ampacity
B. To provide a low-resistance path to ground
, C. To protect conductors from physical damage and serve as a raceway
D. To serve as the primary grounding electrode
CORRECT ANSWER: C. To protect conductors from physical damage and serve as a
raceway
Rationale: Conduit is a raceway that provides physical protection for the conductors it
encloses, shielding them from damage and environmental factors .
Question 12: Which instrument is used to measure the resistance of a circuit or
component?
A. Voltmeter
B. Ammeter
C. Megger
D. Ohmmeter
CORRECT ANSWER: D. Ohmmeter
Rationale: An ohmmeter is used to measure electrical resistance in ohms. It is
commonly found as a function on a multimeter . A megger measures high resistance,
such as insulation resistance.
Question 13: According to the NEC, for a continuous load, a branch circuit must be
sized at what percentage of the load?
A. 80%
B. 100%
C. 125%
D. 150%
CORRECT ANSWER: C. 125%
Rationale: The NEC requires that the branch circuit overcurrent device and conductors
be sized at 125% of the continuous load. This is to account for heat build-up and ensure
reliability .
Question 14: What is the standard frequency for AC power in the United States?
A. 50 Hz
B. 60 Hz
C. 120 Hz
D. 240 Hz
CORRECT ANSWER: B. 60 Hz
Rationale: The standard frequency for alternating current (AC) in North America is 60
Hertz (Hz), meaning the current changes direction 60 times per second .
Question 15: A "short circuit" is best described as:
