National Electrical Practice Exam Questions
and Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
Download Pdf
1. What is the primary purpose of the National Electrical Code
(NEC)?
A. To establish electrical utility rates
B. To provide rules for the safe installation of electrical conductors and
equipment
C. To regulate electrical apprenticeships
D. To establish building material prices
Answer: B. To provide rules for the safe installation of electrical
conductors and equipment
Rationale: The NEC establishes minimum requirements intended to
safeguard people and property from hazards arising from the use of
,electricity. It addresses electrical installations, equipment, wiring
methods, protection, grounding, and related safety requirements.
2. Which unit is used to measure electrical current?
A. Volt
B. Ohm
C. Ampere
D. Watt
Answer: C. Ampere
Rationale: Electrical current is measured in amperes, commonly called
amps. Voltage measures electrical potential difference, ohms measure
resistance, and watts measure electrical power.
3. Which formula represents Ohm's law?
A. P = I × R
B. V = I × R
C. R = P × V
D. I = P × R
Answer: B. V = I × R
Rationale: Ohm's law states that voltage equals current multiplied by
resistance. The relationship can also be rearranged to calculate
current or resistance when the other two quantities are known.
, 4. A 120-volt circuit has a resistance of 20 ohms. Approximately how
much current flows through the circuit?
A. 2 A
B. 4 A
C. 6 A
D. 10 A
Answer: C. 6 A
Rationale: Using Ohm's law, I = V/R. Dividing 120 volts by 20 ohms
gives 6 amperes.
5. What is the electrical power consumed by a 120-volt load drawing
10 amperes?
A. 120 W
B. 600 W
C. 1,000 W
D. 1,200 W
Answer: D. 1,200 W
Rationale: Electrical power can be calculated using P = V × I.
Therefore, 120 volts multiplied by 10 amperes equals 1,200 watts.
6. Which conductor is normally identified as the grounded
conductor in a typical 120/240-volt single-phase system?
, A. Green
B. White or gray
C. Orange
D. Red
Answer: B. White or gray
Rationale: The grounded conductor is generally identified by white or
gray insulation or by permitted equivalent identification methods.
Green and bare conductors are generally associated with equipment
grounding.
7. What is the primary purpose of an equipment grounding
conductor?
A. To carry normal load current
B. To increase circuit voltage
C. To provide a low-impedance fault-current path
D. To reduce conductor resistance
Answer: C. To provide a low-impedance fault-current path
Rationale: The equipment grounding conductor provides a conductive
path for fault current so that overcurrent protection can operate and
disconnect the faulty circuit. It is not intended to carry normal
operating current.
and Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
Download Pdf
1. What is the primary purpose of the National Electrical Code
(NEC)?
A. To establish electrical utility rates
B. To provide rules for the safe installation of electrical conductors and
equipment
C. To regulate electrical apprenticeships
D. To establish building material prices
Answer: B. To provide rules for the safe installation of electrical
conductors and equipment
Rationale: The NEC establishes minimum requirements intended to
safeguard people and property from hazards arising from the use of
,electricity. It addresses electrical installations, equipment, wiring
methods, protection, grounding, and related safety requirements.
2. Which unit is used to measure electrical current?
A. Volt
B. Ohm
C. Ampere
D. Watt
Answer: C. Ampere
Rationale: Electrical current is measured in amperes, commonly called
amps. Voltage measures electrical potential difference, ohms measure
resistance, and watts measure electrical power.
3. Which formula represents Ohm's law?
A. P = I × R
B. V = I × R
C. R = P × V
D. I = P × R
Answer: B. V = I × R
Rationale: Ohm's law states that voltage equals current multiplied by
resistance. The relationship can also be rearranged to calculate
current or resistance when the other two quantities are known.
, 4. A 120-volt circuit has a resistance of 20 ohms. Approximately how
much current flows through the circuit?
A. 2 A
B. 4 A
C. 6 A
D. 10 A
Answer: C. 6 A
Rationale: Using Ohm's law, I = V/R. Dividing 120 volts by 20 ohms
gives 6 amperes.
5. What is the electrical power consumed by a 120-volt load drawing
10 amperes?
A. 120 W
B. 600 W
C. 1,000 W
D. 1,200 W
Answer: D. 1,200 W
Rationale: Electrical power can be calculated using P = V × I.
Therefore, 120 volts multiplied by 10 amperes equals 1,200 watts.
6. Which conductor is normally identified as the grounded
conductor in a typical 120/240-volt single-phase system?
, A. Green
B. White or gray
C. Orange
D. Red
Answer: B. White or gray
Rationale: The grounded conductor is generally identified by white or
gray insulation or by permitted equivalent identification methods.
Green and bare conductors are generally associated with equipment
grounding.
7. What is the primary purpose of an equipment grounding
conductor?
A. To carry normal load current
B. To increase circuit voltage
C. To provide a low-impedance fault-current path
D. To reduce conductor resistance
Answer: C. To provide a low-impedance fault-current path
Rationale: The equipment grounding conductor provides a conductive
path for fault current so that overcurrent protection can operate and
disconnect the faulty circuit. It is not intended to carry normal
operating current.
