Electrician License Exam (Journeyman / State) Prep – Real
Practice Questions, Answers & Detailed Rationales (Updated
2026) | NEC Code, Electrical Theory & Ohm’s Law, Wiring
Methods, Load Calculations, Residential & Commercial Installation,
Motors & Controls, Blueprint Reading, Troubleshooting, OSHA
Safety Standards, State Licensing Exam Concepts
Question 1: According to the NEC, what is the minimum required working clearance
in front of electrical equipment operating at 480V, with exposed live parts on one
side and grounded parts on the other side?
A. 2 feet
B. 3 feet
C. 4 feet
D. 5 feet
CORRECT ANSWER: B. 3 feet
Rationale: NEC Table 110.26(A)(1) specifies minimum working clearances based on
voltage and conditions. For equipment operating at 480V (nominal, phase-to-phase)
with Condition 1 (exposed live parts on one side and grounded parts on the other), the
minimum clearance is 3 feet. This ensures safe access for qualified personnel during
maintenance and operation.
Question 2: What is the maximum allowable voltage drop for a branch circuit
supplying a single receptacle outlet, as recommended by the NEC?
A. 2%
B. 3%
C. 5%
D. 10%
CORRECT ANSWER: B. 3%
Rationale: While the NEC does not enforce voltage drop as a mandatory requirement,
Informational Note No. 4 to NEC 210.19(A)(1) recommends that branch circuit
conductors be sized to prevent a voltage drop exceeding 3% for the farthest outlet. This
recommendation ensures efficient operation of connected equipment and minimizes
energy loss.
Question 3: Which NEC Article specifically addresses the installation requirements
for grounding and bonding of electrical systems?
A. Article 200
B. Article 240
C. Article 250
D. Article 300
CORRECT ANSWER: C. Article 250
,Rationale: NEC Article 250 is dedicated entirely to grounding and bonding
requirements. It covers system grounding, equipment grounding, grounding electrode
systems, bonding of metal parts, and methods to ensure electrical continuity and
safety. Articles 200, 240, and 300 address use and identification of grounded
conductors, overcurrent protection, and general wiring methods, respectively.
Question 4: When installing Type NM cable (Romex) in a residential dwelling, what
is the minimum bending radius allowed?
A. 3 times the cable diameter
B. 4 times the cable diameter
C. 5 times the cable diameter
D. 6 times the cable diameter
CORRECT ANSWER: C. 5 times the cable diameter
Rationale: NEC 334.24 specifies that the bending radius for Type NM cable shall not be
less than five times the diameter of the cable. This prevents damage to the conductors
and insulation during installation, maintaining the integrity and safety of the wiring
system.
Question 5: What is the minimum size copper equipment grounding conductor
required for a 60-ampere circuit breaker?
A. 10 AWG
B. 8 AWG
C. 6 AWG
D. 4 AWG
CORRECT ANSWER: A. 10 AWG
Rationale: NEC Table 250.122 specifies the minimum size of equipment grounding
conductors based on the rating of the overcurrent device. For a 60-ampere circuit, the
table requires a minimum 10 AWG copper equipment grounding conductor. This
ensures adequate fault-current carrying capacity to facilitate overcurrent device
operation during a ground fault.
Question 6: In a dwelling unit, what is the maximum spacing allowed between
receptacle outlets along the floor line of any wall space?
A. 6 feet
B. 8 feet
C. 10 feet
D. 12 feet
CORRECT ANSWER: D. 12 feet
Rationale: NEC 210.52(A)(1) requires that receptacle outlets be installed so that no
point along the floor line in any wall space is more than 6 feet from a receptacle outlet.
,This effectively mandates a maximum spacing of 12 feet between receptacles, ensuring
convenient access to power and reducing the need for extension cords.
Question 7: Which of the following is NOT permitted as a grounding electrode under
NEC Article 250?
A. Metal underground water pipe
B. Concrete-encased electrode (Ufer ground)
C. Gas piping system
D. Ground ring
CORRECT ANSWER: C. Gas piping system
Rationale: NEC 250.52(B) explicitly prohibits the use of metal underground gas piping
systems as grounding electrodes due to the risk of fire or explosion if fault current
travels through the gas line. Acceptable electrodes include metal water pipes,
concrete-encased electrodes, ground rings, and others listed in 250.52(A).
Question 8: What is the minimum ampacity required for branch circuit conductors
supplying a continuous load of 24 amperes?
A. 24 amperes
B. 28.8 amperes
C. 30 amperes
D. 32 amperes
CORRECT ANSWER: C. 30 amperes
Rationale: NEC 210.19(A)(1) requires that branch circuit conductors supplying
continuous loads (operating for 3 hours or more) have an ampacity of not less than
125% of the continuous load. 24A × 1.25 = 30A. Therefore, conductors must have a
minimum ampacity of 30 amperes, typically requiring 10 AWG copper conductors at
60°C or 12 AWG at 75°C depending on termination ratings.
Question 9: Which type of conduit is permitted for use in wet locations without
additional protection?
A. EMT (Electrical Metallic Tubing)
B. RMC (Rigid Metal Conduit)
C. IMC (Intermediate Metal Conduit)
D. Both B and C
CORRECT ANSWER: D. Both B and C
Rationale: NEC 344.10 and 342.10 permit Rigid Metal Conduit (RMC) and Intermediate
Metal Conduit (IMC) for use in wet locations when properly installed with corrosion-
resistant fittings. EMT (358.10) is generally not permitted in wet locations unless
specifically listed for such use or protected from corrosion.
, Question 10: What is the maximum number of 90-degree bends allowed in a single
conduit run between pull points?
A. 2
B. 3
C. 4
D. 5
CORRECT ANSWER: C. 4
Rationale: NEC 358.26 (for EMT) and similar sections for other conduit types limit the
total degrees of bend in a single conduit run between boxes, conduit bodies, or other
pull points to 360 degrees. Since each 90-degree bend equals 90 degrees, a maximum
of four 90-degree bends (4 × 90° = 360°) is permitted to facilitate wire pulling and
prevent conductor damage.
Question 11: For a 120/240V, single-phase, 3-wire dwelling service, what is the
minimum service disconnect rating required by the NEC?
A. 60 amperes
B. 100 amperes
C. 125 amperes
D. 150 amperes
CORRECT ANSWER: B. 100 amperes
Rationale: NEC 230.79(C) mandates that the service disconnecting means for a one-
family dwelling with a 120/240V, single-phase supply shall have a rating of not less than
100 amperes. This ensures adequate capacity for typical residential loads and future
expansion while maintaining safety margins.
Question 12: Which of the following conductors is identified as a grounded (neutral)
conductor in a flexible cord?
A. Green insulation
B. White or gray insulation
C. Bare conductor
D. Black insulation
CORRECT ANSWER: B. White or gray insulation
Rationale: NEC 200.10(C) requires that the grounded conductor (neutral) in flexible
cords be identified by a white or gray outer finish or by three continuous white stripes on
other than green insulation. Green or bare conductors are reserved for equipment
grounding conductors per NEC 250.119.
Question 13: What is the minimum depth requirement for a ground rod electrode
driven into the earth?
Practice Questions, Answers & Detailed Rationales (Updated
2026) | NEC Code, Electrical Theory & Ohm’s Law, Wiring
Methods, Load Calculations, Residential & Commercial Installation,
Motors & Controls, Blueprint Reading, Troubleshooting, OSHA
Safety Standards, State Licensing Exam Concepts
Question 1: According to the NEC, what is the minimum required working clearance
in front of electrical equipment operating at 480V, with exposed live parts on one
side and grounded parts on the other side?
A. 2 feet
B. 3 feet
C. 4 feet
D. 5 feet
CORRECT ANSWER: B. 3 feet
Rationale: NEC Table 110.26(A)(1) specifies minimum working clearances based on
voltage and conditions. For equipment operating at 480V (nominal, phase-to-phase)
with Condition 1 (exposed live parts on one side and grounded parts on the other), the
minimum clearance is 3 feet. This ensures safe access for qualified personnel during
maintenance and operation.
Question 2: What is the maximum allowable voltage drop for a branch circuit
supplying a single receptacle outlet, as recommended by the NEC?
A. 2%
B. 3%
C. 5%
D. 10%
CORRECT ANSWER: B. 3%
Rationale: While the NEC does not enforce voltage drop as a mandatory requirement,
Informational Note No. 4 to NEC 210.19(A)(1) recommends that branch circuit
conductors be sized to prevent a voltage drop exceeding 3% for the farthest outlet. This
recommendation ensures efficient operation of connected equipment and minimizes
energy loss.
Question 3: Which NEC Article specifically addresses the installation requirements
for grounding and bonding of electrical systems?
A. Article 200
B. Article 240
C. Article 250
D. Article 300
CORRECT ANSWER: C. Article 250
,Rationale: NEC Article 250 is dedicated entirely to grounding and bonding
requirements. It covers system grounding, equipment grounding, grounding electrode
systems, bonding of metal parts, and methods to ensure electrical continuity and
safety. Articles 200, 240, and 300 address use and identification of grounded
conductors, overcurrent protection, and general wiring methods, respectively.
Question 4: When installing Type NM cable (Romex) in a residential dwelling, what
is the minimum bending radius allowed?
A. 3 times the cable diameter
B. 4 times the cable diameter
C. 5 times the cable diameter
D. 6 times the cable diameter
CORRECT ANSWER: C. 5 times the cable diameter
Rationale: NEC 334.24 specifies that the bending radius for Type NM cable shall not be
less than five times the diameter of the cable. This prevents damage to the conductors
and insulation during installation, maintaining the integrity and safety of the wiring
system.
Question 5: What is the minimum size copper equipment grounding conductor
required for a 60-ampere circuit breaker?
A. 10 AWG
B. 8 AWG
C. 6 AWG
D. 4 AWG
CORRECT ANSWER: A. 10 AWG
Rationale: NEC Table 250.122 specifies the minimum size of equipment grounding
conductors based on the rating of the overcurrent device. For a 60-ampere circuit, the
table requires a minimum 10 AWG copper equipment grounding conductor. This
ensures adequate fault-current carrying capacity to facilitate overcurrent device
operation during a ground fault.
Question 6: In a dwelling unit, what is the maximum spacing allowed between
receptacle outlets along the floor line of any wall space?
A. 6 feet
B. 8 feet
C. 10 feet
D. 12 feet
CORRECT ANSWER: D. 12 feet
Rationale: NEC 210.52(A)(1) requires that receptacle outlets be installed so that no
point along the floor line in any wall space is more than 6 feet from a receptacle outlet.
,This effectively mandates a maximum spacing of 12 feet between receptacles, ensuring
convenient access to power and reducing the need for extension cords.
Question 7: Which of the following is NOT permitted as a grounding electrode under
NEC Article 250?
A. Metal underground water pipe
B. Concrete-encased electrode (Ufer ground)
C. Gas piping system
D. Ground ring
CORRECT ANSWER: C. Gas piping system
Rationale: NEC 250.52(B) explicitly prohibits the use of metal underground gas piping
systems as grounding electrodes due to the risk of fire or explosion if fault current
travels through the gas line. Acceptable electrodes include metal water pipes,
concrete-encased electrodes, ground rings, and others listed in 250.52(A).
Question 8: What is the minimum ampacity required for branch circuit conductors
supplying a continuous load of 24 amperes?
A. 24 amperes
B. 28.8 amperes
C. 30 amperes
D. 32 amperes
CORRECT ANSWER: C. 30 amperes
Rationale: NEC 210.19(A)(1) requires that branch circuit conductors supplying
continuous loads (operating for 3 hours or more) have an ampacity of not less than
125% of the continuous load. 24A × 1.25 = 30A. Therefore, conductors must have a
minimum ampacity of 30 amperes, typically requiring 10 AWG copper conductors at
60°C or 12 AWG at 75°C depending on termination ratings.
Question 9: Which type of conduit is permitted for use in wet locations without
additional protection?
A. EMT (Electrical Metallic Tubing)
B. RMC (Rigid Metal Conduit)
C. IMC (Intermediate Metal Conduit)
D. Both B and C
CORRECT ANSWER: D. Both B and C
Rationale: NEC 344.10 and 342.10 permit Rigid Metal Conduit (RMC) and Intermediate
Metal Conduit (IMC) for use in wet locations when properly installed with corrosion-
resistant fittings. EMT (358.10) is generally not permitted in wet locations unless
specifically listed for such use or protected from corrosion.
, Question 10: What is the maximum number of 90-degree bends allowed in a single
conduit run between pull points?
A. 2
B. 3
C. 4
D. 5
CORRECT ANSWER: C. 4
Rationale: NEC 358.26 (for EMT) and similar sections for other conduit types limit the
total degrees of bend in a single conduit run between boxes, conduit bodies, or other
pull points to 360 degrees. Since each 90-degree bend equals 90 degrees, a maximum
of four 90-degree bends (4 × 90° = 360°) is permitted to facilitate wire pulling and
prevent conductor damage.
Question 11: For a 120/240V, single-phase, 3-wire dwelling service, what is the
minimum service disconnect rating required by the NEC?
A. 60 amperes
B. 100 amperes
C. 125 amperes
D. 150 amperes
CORRECT ANSWER: B. 100 amperes
Rationale: NEC 230.79(C) mandates that the service disconnecting means for a one-
family dwelling with a 120/240V, single-phase supply shall have a rating of not less than
100 amperes. This ensures adequate capacity for typical residential loads and future
expansion while maintaining safety margins.
Question 12: Which of the following conductors is identified as a grounded (neutral)
conductor in a flexible cord?
A. Green insulation
B. White or gray insulation
C. Bare conductor
D. Black insulation
CORRECT ANSWER: B. White or gray insulation
Rationale: NEC 200.10(C) requires that the grounded conductor (neutral) in flexible
cords be identified by a white or gray outer finish or by three continuous white stripes on
other than green insulation. Green or bare conductors are reserved for equipment
grounding conductors per NEC 250.119.
Question 13: What is the minimum depth requirement for a ground rod electrode
driven into the earth?
