City of Rockford – Electrical Contractor
Examination Questions and Correct Answers
(Verified Answers) Plus Rationale 2027 Q&A|
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1. What is the primary purpose of the National Electrical Code (NEC)?
A. To establish electrical utility rates
B. To regulate electrical product manufacturing
C. To provide practical safeguards for persons and property from
hazards arising from the use of electricity
D. To establish contractor licensing fees
Correct Answer: C. To provide practical safeguards for persons and
property from hazards arising from the use of electricity
Rationale: The NEC establishes minimum safety requirements for
electrical installations. Its purpose is to protect people and property
from hazards such as electric shock, fire, and electrical-system
,failures. It is not primarily a licensing, utility-rate, or product-
manufacturing standard.
2. In an electrical installation, what is the purpose of the equipment
grounding conductor?
A. To carry normal circuit current
B. To provide a low-impedance path for fault current
C. To increase circuit voltage
D. To replace the grounded conductor
Correct Answer: B. To provide a low-impedance path for fault current
Rationale: The equipment grounding conductor connects normally
non-current-carrying metal parts to the grounding system. If a fault
energizes exposed metal, the grounding path helps carry sufficient
fault current to operate the overcurrent protective device.
3. A 120-volt circuit has a resistance of 20 ohms. Approximately how
much current will flow?
A. 2 A
B. 4 A
,C. 6 A
D. 10 A
Correct Answer: B. 6 A
Rationale: Ohm's law is I = E/R. Therefore, I = 120 ÷ 20 = 6 amperes.
Understanding voltage, current, resistance, and their mathematical
relationship is fundamental to electrical calculations.
4. Which device is specifically designed to interrupt a circuit when it
detects a potentially dangerous ground-fault current?
A. AFCI
B. GFCI
C. Transformer
D. Disconnect switch
Correct Answer: B. GFCI
Rationale: A Ground-Fault Circuit-Interrupter monitors current
balance between the ungrounded and grounded conductors. When a
difference indicates current may be flowing through an unintended
path, the device trips rapidly to reduce shock hazards.
, 5. What is the unit of electrical power?
A. Ohm
B. Volt
C. Ampere
D. Watt
Correct Answer: D. Watt
Rationale: Electrical power is measured in watts. For a simple DC or
resistive circuit, power can be calculated using P = E × I, where P is
watts, E is volts, and I is amperes.
6. A 240-volt single-phase load draws 20 amperes. What is its
approximate power consumption?
A. 1,200 W
B. 2,400 W
C. 4,800 W
D. 9,600 W
Correct Answer: C. 4,800 W
Rationale: Using P = E × I, the power is 240 × 20 = 4,800 watts. This
calculation assumes a unity power factor or a purely resistive load.
Examination 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 regulate electrical product manufacturing
C. To provide practical safeguards for persons and property from
hazards arising from the use of electricity
D. To establish contractor licensing fees
Correct Answer: C. To provide practical safeguards for persons and
property from hazards arising from the use of electricity
Rationale: The NEC establishes minimum safety requirements for
electrical installations. Its purpose is to protect people and property
from hazards such as electric shock, fire, and electrical-system
,failures. It is not primarily a licensing, utility-rate, or product-
manufacturing standard.
2. In an electrical installation, what is the purpose of the equipment
grounding conductor?
A. To carry normal circuit current
B. To provide a low-impedance path for fault current
C. To increase circuit voltage
D. To replace the grounded conductor
Correct Answer: B. To provide a low-impedance path for fault current
Rationale: The equipment grounding conductor connects normally
non-current-carrying metal parts to the grounding system. If a fault
energizes exposed metal, the grounding path helps carry sufficient
fault current to operate the overcurrent protective device.
3. A 120-volt circuit has a resistance of 20 ohms. Approximately how
much current will flow?
A. 2 A
B. 4 A
,C. 6 A
D. 10 A
Correct Answer: B. 6 A
Rationale: Ohm's law is I = E/R. Therefore, I = 120 ÷ 20 = 6 amperes.
Understanding voltage, current, resistance, and their mathematical
relationship is fundamental to electrical calculations.
4. Which device is specifically designed to interrupt a circuit when it
detects a potentially dangerous ground-fault current?
A. AFCI
B. GFCI
C. Transformer
D. Disconnect switch
Correct Answer: B. GFCI
Rationale: A Ground-Fault Circuit-Interrupter monitors current
balance between the ungrounded and grounded conductors. When a
difference indicates current may be flowing through an unintended
path, the device trips rapidly to reduce shock hazards.
, 5. What is the unit of electrical power?
A. Ohm
B. Volt
C. Ampere
D. Watt
Correct Answer: D. Watt
Rationale: Electrical power is measured in watts. For a simple DC or
resistive circuit, power can be calculated using P = E × I, where P is
watts, E is volts, and I is amperes.
6. A 240-volt single-phase load draws 20 amperes. What is its
approximate power consumption?
A. 1,200 W
B. 2,400 W
C. 4,800 W
D. 9,600 W
Correct Answer: C. 4,800 W
Rationale: Using P = E × I, the power is 240 × 20 = 4,800 watts. This
calculation assumes a unity power factor or a purely resistive load.
