North Carolina Electrical Contractor Exam 2026 – 190 Practice
Questions with Answers & Detailed Rationales, NEC 2023, NC
Administrative Code, Electrical Theory, Wiring Methods, Business
Practices, Code Compliance & Safety
Section 1: General Electrical Knowledge & Ohm's Law (Questions 1–25)
Question 1
A 120-volt branch circuit has a measured resistance of 24 ohms at the connected load.
Assuming a purely resistive load, what current will flow?
A. 2 A
B. 5 A
C. 24 A
D. 48 A
Correct Answer: B
Explanation: Using Ohm's law, I = E/R. Therefore, 120 volts divided by 24 ohms equals 5
amperes.
Question 2
A 240-volt single-phase heater draws 18 amperes. What is its approximate power
consumption?
A. 2.16 kW
B. 3.24 kW
C. 4.32 kW
D. 5.40 kW
,Correct Answer: C
Explanation: Power in a resistive circuit is P = E × I. Thus, 240 V × 18 A = 4,320 W or 4.32 kW.
Question 3
A 480-volt, three-phase motor circuit has a continuous load of 42 amperes. The motor
nameplate current is 42 amperes. What minimum ampacity must the branch-circuit
conductors have, assuming no adjustment or correction factors reduce conductor ampacity?
A. 42 A
B. 46.2 A
C. 52.5 A
D. 60 A
Correct Answer: C
Explanation: For a continuous motor load, conductor ampacity must be at least 125% of the
applicable motor current. 42 A × 1.25 = 52.5 A.
Question 4
A 75-kVA, three-phase transformer has a primary voltage of 480 volts. Approximately what is
the primary full-load current?
A. 62.5 A
B. 78.1 A
C. 90.2 A
D. 156.3 A
,Correct Answer: C
Explanation: Three-phase transformer current is calculated as VA ÷ (√3 × V). Thus, 75,000 ÷
(1.732 × 480) ≈ 90.2 A.
Question 5
A 120/240-volt single-phase service supplies a dwelling with a calculated service load of 185
amperes. The service conductors are installed in a raceway and the temperature and
termination limitations permit their selected insulation rating. Which service rating is the
minimum standard rating that can be selected when permitted by the applicable standard
ampere ratings?
A. 185 A
B. 190 A
C. 200 A
D. 225 A
Correct Answer: C
Explanation: Where the calculated load falls between standard ampere ratings, the next
higher standard rating may be permitted under applicable NEC rules when conditions for
using the next higher rating are satisfied.
Question 6
An electrical contractor installs four current-carrying conductors in a raceway. The
conductors are rated 90°C, but the equipment terminations are limited to 75°C. Which
temperature rating is generally used for determining the conductor ampacity at the
equipment terminations?
A. 60°C
B. 75°C
, C. 90°C
D. 105°C
Correct Answer: B
Explanation: The conductor may have a 90°C insulation rating, but termination temperature
limitations must be observed. For equipment rated over the applicable small-conductor
ranges, 75°C terminations are commonly used.
Question 7
A feeder supplies a continuous lighting load of 64 amperes and a noncontinuous load of 40
amperes. What minimum calculated feeder ampacity is required before applying other
applicable factors?
A. 80 A
B. 104 A
C. 120 A
D. 128 A
Correct Answer: C
Explanation: The continuous load is multiplied by 125%: 64 × 1.25 = 80 A. Adding the 40-A
noncontinuous load gives 120 A.
Question 8
A 230 kV transmission line is being constructed. Per NESC C2-2023 Rule 232, what is the
minimum vertical clearance above a public highway at maximum sag for a line with a
maximum operating voltage of 230 kV?
A. 18.5 ft (5.64 m)
Questions with Answers & Detailed Rationales, NEC 2023, NC
Administrative Code, Electrical Theory, Wiring Methods, Business
Practices, Code Compliance & Safety
Section 1: General Electrical Knowledge & Ohm's Law (Questions 1–25)
Question 1
A 120-volt branch circuit has a measured resistance of 24 ohms at the connected load.
Assuming a purely resistive load, what current will flow?
A. 2 A
B. 5 A
C. 24 A
D. 48 A
Correct Answer: B
Explanation: Using Ohm's law, I = E/R. Therefore, 120 volts divided by 24 ohms equals 5
amperes.
Question 2
A 240-volt single-phase heater draws 18 amperes. What is its approximate power
consumption?
A. 2.16 kW
B. 3.24 kW
C. 4.32 kW
D. 5.40 kW
,Correct Answer: C
Explanation: Power in a resistive circuit is P = E × I. Thus, 240 V × 18 A = 4,320 W or 4.32 kW.
Question 3
A 480-volt, three-phase motor circuit has a continuous load of 42 amperes. The motor
nameplate current is 42 amperes. What minimum ampacity must the branch-circuit
conductors have, assuming no adjustment or correction factors reduce conductor ampacity?
A. 42 A
B. 46.2 A
C. 52.5 A
D. 60 A
Correct Answer: C
Explanation: For a continuous motor load, conductor ampacity must be at least 125% of the
applicable motor current. 42 A × 1.25 = 52.5 A.
Question 4
A 75-kVA, three-phase transformer has a primary voltage of 480 volts. Approximately what is
the primary full-load current?
A. 62.5 A
B. 78.1 A
C. 90.2 A
D. 156.3 A
,Correct Answer: C
Explanation: Three-phase transformer current is calculated as VA ÷ (√3 × V). Thus, 75,000 ÷
(1.732 × 480) ≈ 90.2 A.
Question 5
A 120/240-volt single-phase service supplies a dwelling with a calculated service load of 185
amperes. The service conductors are installed in a raceway and the temperature and
termination limitations permit their selected insulation rating. Which service rating is the
minimum standard rating that can be selected when permitted by the applicable standard
ampere ratings?
A. 185 A
B. 190 A
C. 200 A
D. 225 A
Correct Answer: C
Explanation: Where the calculated load falls between standard ampere ratings, the next
higher standard rating may be permitted under applicable NEC rules when conditions for
using the next higher rating are satisfied.
Question 6
An electrical contractor installs four current-carrying conductors in a raceway. The
conductors are rated 90°C, but the equipment terminations are limited to 75°C. Which
temperature rating is generally used for determining the conductor ampacity at the
equipment terminations?
A. 60°C
B. 75°C
, C. 90°C
D. 105°C
Correct Answer: B
Explanation: The conductor may have a 90°C insulation rating, but termination temperature
limitations must be observed. For equipment rated over the applicable small-conductor
ranges, 75°C terminations are commonly used.
Question 7
A feeder supplies a continuous lighting load of 64 amperes and a noncontinuous load of 40
amperes. What minimum calculated feeder ampacity is required before applying other
applicable factors?
A. 80 A
B. 104 A
C. 120 A
D. 128 A
Correct Answer: C
Explanation: The continuous load is multiplied by 125%: 64 × 1.25 = 80 A. Adding the 40-A
noncontinuous load gives 120 A.
Question 8
A 230 kV transmission line is being constructed. Per NESC C2-2023 Rule 232, what is the
minimum vertical clearance above a public highway at maximum sag for a line with a
maximum operating voltage of 230 kV?
A. 18.5 ft (5.64 m)
