Electrician License Exam (Journeyman / State) Prep – Practice
Questions, Answers & Detailed Rationales (Updated 2026) | NEC Code
& Regulations, Electrical Theory (Ohm’s Law), Wiring Methods &
Installation, Circuit Calculations & Load Sizing, Motors & Controls,
Blueprint Reading, Troubleshooting Techniques, Safety Standards & OSHA
Question 1: What is the minimum required working clearance in front of electrical
equipment rated 480V line-to-line with exposed live parts on one side and
grounded parts on the other, per NEC Table 110.26(A)(1)?
A. 3 feet
B. 4 feet
C. 6 feet
D. 8 feet
CORRECT ANSWER: A. 3 feet
Rationale: NEC Table 110.26(A)(1) specifies working clearances based on voltage to
ground and conditions. A 480V line-to-line system has 277V to ground, which falls in the
151–600V range. Condition 1 applies when exposed live parts are on one side and
grounded parts on the other. For 151–600V under Condition 1, the minimum clearance
is 3 feet.
Question 2: Which NEC article specifically addresses the installation requirements
for grounding and bonding of electrical systems?
A. Article 210
B. Article 250
C. Article 310
D. Article 430
CORRECT ANSWER: B. Article 250
Rationale: NEC Article 250 is dedicated to grounding and bonding requirements,
including system grounding, equipment grounding, grounding electrode systems, and
bonding of non-current-carrying metal parts. Articles 210, 310, and 430 cover branch
circuits, conductor specifications, and motors, respectively.
Question 3: What is the maximum allowable voltage drop for a branch circuit
supplying a single receptacle for a continuous load, 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. 2 to NEC 210.19(A)(1) recommends that branch circuit
,conductors be sized to limit voltage drop to 3% for reasonable efficiency of operation.
The combined voltage drop for feeder and branch circuit should not exceed 5%.
Question 4: A 20-ampere, 120-volt branch circuit supplies lighting outlets in a
dwelling unit. What is the maximum number of outlets permitted on this circuit per
NEC 220.14(I)?
A. 10
B. 12
C. 13
D. 15
CORRECT ANSWER: C. 13
Rationale: NEC 220.14(I) assigns a load of 180 volt-amperes per outlet for general-
purpose receptacles and lighting outlets in dwelling units. For a 20A, 120V circuit, the
maximum load is 20A × 120V = 2400 VA. Dividing 2400 VA by 180 VA per outlet yields
13.33, so the maximum number of outlets is 13.
Question 5: Which type of conductor insulation is suitable for use in wet locations
and rated for 90°C dry and 75°C wet?
A. THHN
B. THWN-2
C. XHHW
D. UF
CORRECT ANSWER: B. THWN-2
Rationale: THWN-2 conductors are rated for 90°C in dry locations and 75°C in wet
locations, and are suitable for wet locations per NEC Table 310.104(A). THHN is only
rated for dry locations. XHHW is rated 90°C dry/wet but is less common for general wet
location use. UF cable is a cable assembly, not a conductor insulation type.
Question 6: What is the minimum size equipment grounding conductor required for
a 60-ampere overcurrent device protecting a feeder circuit, per NEC Table 250.122?
A. 10 AWG copper
B. 8 AWG copper
C. 6 AWG copper
D. 4 AWG copper
CORRECT ANSWER: A. 10 AWG copper
Rationale: NEC Table 250.122 specifies the minimum size equipment grounding
conductor based on the rating of the overcurrent device. For a 60-ampere device, the
table requires a 10 AWG copper equipment grounding conductor. This applies
regardless of the ungrounded conductor size, unless adjusted for parallel conductors or
other specific conditions.
,Question 7: In a dwelling unit, what is the required arc-fault circuit interrupter
(AFCI) protection for 120-volt, single-phase, 15- and 20-ampere branch circuits
supplying outlets in bedrooms?
A. Not required if GFCI is installed
B. Required only for new construction
C. Required for all such circuits per NEC 210.12
D. Required only for circuits with lighting outlets
CORRECT ANSWER: C. Required for all such circuits per NEC 210.12
Rationale: NEC 210.12(A) requires AFCI protection for all 120-volt, single-phase, 15-
and 20-ampere branch circuits supplying outlets or devices in dwelling unit bedrooms.
This requirement applies to both new and existing installations where modifications are
made, and is independent of GFCI requirements.
Question 8: What is the minimum burial depth for Type UF cable installed under a
residential driveway without concrete encasement, per NEC Table 300.5?
A. 12 inches
B. 18 inches
C. 24 inches
D. 30 inches
CORRECT ANSWER: B. 18 inches
Rationale: NEC Table 300.5 specifies burial depths for underground wiring methods. For
Type UF cable under a residential driveway (not under a street or public way), the
minimum cover requirement is 18 inches. Concrete encasement would reduce the
requirement to 12 inches, but the question specifies no encasement.
Question 9: Which of the following is NOT a permitted method for identifying an
equipment grounding conductor larger than 6 AWG?
A. Continuous green color
B. Continuous green with yellow stripe
C. White or gray insulation with green tape at terminations
D. Stripping the insulation to expose bare copper at terminations only
CORRECT ANSWER: D. Stripping the insulation to expose bare copper at
terminations only
Rationale: NEC 250.119(B) permits identification of equipment grounding conductors
larger than 6 AWG by: (1) continuous green color, (2) continuous green with yellow
stripe, or (3) white or gray insulation with green marking at terminations. Simply
stripping insulation to expose bare copper at terminations is not a permitted
identification method per code.
Question 10: What is the maximum number of 90-degree bends allowed in a single
run of conduit between pull points, per NEC 358.26 for EMT?
, A. 2
B. 3
C. 4
D. 5
CORRECT ANSWER: C. 4
Rationale: NEC 358.26 states that there shall not be more than the equivalent of four
quarter bends (360 degrees total) between pull points in a single run of Electrical
Metallic Tubing (EMT). This applies to all conduit types unless otherwise specified in
their respective articles.
Question 11: A 3-phase, 4-wire, 208Y/120-volt system supplies a commercial
building. What is the voltage between any ungrounded conductor and the grounded
conductor?
A. 120 volts
B. 208 volts
C. 240 volts
D. 480 volts
CORRECT ANSWER: A. 120 volts
Rationale: In a 208Y/120-volt wye-connected system, the voltage between any
ungrounded (phase) conductor and the grounded (neutral) conductor is 120 volts. The
voltage between any two ungrounded conductors is 208 volts. This is a standard
configuration for commercial lighting and receptacle loads.
Question 12: Which NEC section requires that all 125-volt, single-phase, 15- and
20-ampere receptacles installed in dwelling unit bathrooms have GFCI protection?
A. 210.8(A)(1)
B. 210.8(B)(1)
C. 210.12(A)
D. 406.4(D)
CORRECT ANSWER: A. 210.8(A)(1)
Rationale: NEC 210.8(A)(1) specifically requires GFCI protection for all 125-volt, single-
phase, 15- and 20-ampere receptacles installed in dwelling unit bathrooms. Section
210.8(B) applies to non-dwelling units, 210.12 addresses AFCI protection, and 406.4(D)
covers receptacle replacement requirements.
Question 13: What is the minimum size copper grounding electrode conductor
required when connecting to a concrete-encased electrode (Ufer ground) for a
service with 4/0 AWG ungrounded service conductors?
A. 4 AWG
B. 2 AWG
Questions, Answers & Detailed Rationales (Updated 2026) | NEC Code
& Regulations, Electrical Theory (Ohm’s Law), Wiring Methods &
Installation, Circuit Calculations & Load Sizing, Motors & Controls,
Blueprint Reading, Troubleshooting Techniques, Safety Standards & OSHA
Question 1: What is the minimum required working clearance in front of electrical
equipment rated 480V line-to-line with exposed live parts on one side and
grounded parts on the other, per NEC Table 110.26(A)(1)?
A. 3 feet
B. 4 feet
C. 6 feet
D. 8 feet
CORRECT ANSWER: A. 3 feet
Rationale: NEC Table 110.26(A)(1) specifies working clearances based on voltage to
ground and conditions. A 480V line-to-line system has 277V to ground, which falls in the
151–600V range. Condition 1 applies when exposed live parts are on one side and
grounded parts on the other. For 151–600V under Condition 1, the minimum clearance
is 3 feet.
Question 2: Which NEC article specifically addresses the installation requirements
for grounding and bonding of electrical systems?
A. Article 210
B. Article 250
C. Article 310
D. Article 430
CORRECT ANSWER: B. Article 250
Rationale: NEC Article 250 is dedicated to grounding and bonding requirements,
including system grounding, equipment grounding, grounding electrode systems, and
bonding of non-current-carrying metal parts. Articles 210, 310, and 430 cover branch
circuits, conductor specifications, and motors, respectively.
Question 3: What is the maximum allowable voltage drop for a branch circuit
supplying a single receptacle for a continuous load, 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. 2 to NEC 210.19(A)(1) recommends that branch circuit
,conductors be sized to limit voltage drop to 3% for reasonable efficiency of operation.
The combined voltage drop for feeder and branch circuit should not exceed 5%.
Question 4: A 20-ampere, 120-volt branch circuit supplies lighting outlets in a
dwelling unit. What is the maximum number of outlets permitted on this circuit per
NEC 220.14(I)?
A. 10
B. 12
C. 13
D. 15
CORRECT ANSWER: C. 13
Rationale: NEC 220.14(I) assigns a load of 180 volt-amperes per outlet for general-
purpose receptacles and lighting outlets in dwelling units. For a 20A, 120V circuit, the
maximum load is 20A × 120V = 2400 VA. Dividing 2400 VA by 180 VA per outlet yields
13.33, so the maximum number of outlets is 13.
Question 5: Which type of conductor insulation is suitable for use in wet locations
and rated for 90°C dry and 75°C wet?
A. THHN
B. THWN-2
C. XHHW
D. UF
CORRECT ANSWER: B. THWN-2
Rationale: THWN-2 conductors are rated for 90°C in dry locations and 75°C in wet
locations, and are suitable for wet locations per NEC Table 310.104(A). THHN is only
rated for dry locations. XHHW is rated 90°C dry/wet but is less common for general wet
location use. UF cable is a cable assembly, not a conductor insulation type.
Question 6: What is the minimum size equipment grounding conductor required for
a 60-ampere overcurrent device protecting a feeder circuit, per NEC Table 250.122?
A. 10 AWG copper
B. 8 AWG copper
C. 6 AWG copper
D. 4 AWG copper
CORRECT ANSWER: A. 10 AWG copper
Rationale: NEC Table 250.122 specifies the minimum size equipment grounding
conductor based on the rating of the overcurrent device. For a 60-ampere device, the
table requires a 10 AWG copper equipment grounding conductor. This applies
regardless of the ungrounded conductor size, unless adjusted for parallel conductors or
other specific conditions.
,Question 7: In a dwelling unit, what is the required arc-fault circuit interrupter
(AFCI) protection for 120-volt, single-phase, 15- and 20-ampere branch circuits
supplying outlets in bedrooms?
A. Not required if GFCI is installed
B. Required only for new construction
C. Required for all such circuits per NEC 210.12
D. Required only for circuits with lighting outlets
CORRECT ANSWER: C. Required for all such circuits per NEC 210.12
Rationale: NEC 210.12(A) requires AFCI protection for all 120-volt, single-phase, 15-
and 20-ampere branch circuits supplying outlets or devices in dwelling unit bedrooms.
This requirement applies to both new and existing installations where modifications are
made, and is independent of GFCI requirements.
Question 8: What is the minimum burial depth for Type UF cable installed under a
residential driveway without concrete encasement, per NEC Table 300.5?
A. 12 inches
B. 18 inches
C. 24 inches
D. 30 inches
CORRECT ANSWER: B. 18 inches
Rationale: NEC Table 300.5 specifies burial depths for underground wiring methods. For
Type UF cable under a residential driveway (not under a street or public way), the
minimum cover requirement is 18 inches. Concrete encasement would reduce the
requirement to 12 inches, but the question specifies no encasement.
Question 9: Which of the following is NOT a permitted method for identifying an
equipment grounding conductor larger than 6 AWG?
A. Continuous green color
B. Continuous green with yellow stripe
C. White or gray insulation with green tape at terminations
D. Stripping the insulation to expose bare copper at terminations only
CORRECT ANSWER: D. Stripping the insulation to expose bare copper at
terminations only
Rationale: NEC 250.119(B) permits identification of equipment grounding conductors
larger than 6 AWG by: (1) continuous green color, (2) continuous green with yellow
stripe, or (3) white or gray insulation with green marking at terminations. Simply
stripping insulation to expose bare copper at terminations is not a permitted
identification method per code.
Question 10: What is the maximum number of 90-degree bends allowed in a single
run of conduit between pull points, per NEC 358.26 for EMT?
, A. 2
B. 3
C. 4
D. 5
CORRECT ANSWER: C. 4
Rationale: NEC 358.26 states that there shall not be more than the equivalent of four
quarter bends (360 degrees total) between pull points in a single run of Electrical
Metallic Tubing (EMT). This applies to all conduit types unless otherwise specified in
their respective articles.
Question 11: A 3-phase, 4-wire, 208Y/120-volt system supplies a commercial
building. What is the voltage between any ungrounded conductor and the grounded
conductor?
A. 120 volts
B. 208 volts
C. 240 volts
D. 480 volts
CORRECT ANSWER: A. 120 volts
Rationale: In a 208Y/120-volt wye-connected system, the voltage between any
ungrounded (phase) conductor and the grounded (neutral) conductor is 120 volts. The
voltage between any two ungrounded conductors is 208 volts. This is a standard
configuration for commercial lighting and receptacle loads.
Question 12: Which NEC section requires that all 125-volt, single-phase, 15- and
20-ampere receptacles installed in dwelling unit bathrooms have GFCI protection?
A. 210.8(A)(1)
B. 210.8(B)(1)
C. 210.12(A)
D. 406.4(D)
CORRECT ANSWER: A. 210.8(A)(1)
Rationale: NEC 210.8(A)(1) specifically requires GFCI protection for all 125-volt, single-
phase, 15- and 20-ampere receptacles installed in dwelling unit bathrooms. Section
210.8(B) applies to non-dwelling units, 210.12 addresses AFCI protection, and 406.4(D)
covers receptacle replacement requirements.
Question 13: What is the minimum size copper grounding electrode conductor
required when connecting to a concrete-encased electrode (Ufer ground) for a
service with 4/0 AWG ungrounded service conductors?
A. 4 AWG
B. 2 AWG
