South Carolina Residential Electrical Contractor
Examination (Technical 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) in
residential electrical installations?
A. To establish electrical utility rates
B. To provide practical safeguards for persons and property from
electrical hazards
C. To determine the cost of electrical labor
D. To regulate the sale of electrical appliances
Answer: B. To provide practical safeguards for persons and property
from electrical hazards
Rationale: The NEC establishes minimum requirements intended to
protect people and property from hazards arising from the use of
electricity. It addresses wiring methods, equipment installation,
,overcurrent protection, grounding, and many other safety
considerations.
2. In a typical 120/240-volt single-phase residential system, what is
the voltage measured between the two ungrounded conductors?
A. 120 volts
B. 208 volts
C. 240 volts
D. 480 volts
Answer: C. 240 volts
Rationale: A typical residential single-phase service has two
ungrounded conductors, each approximately 120 volts to the neutral.
Because they are opposite in phase, the voltage between them is
approximately 240 volts.
3. What is the function of a circuit breaker in a residential branch
circuit?
A. To increase circuit voltage
B. To provide overcurrent protection
,C. To eliminate the need for grounding
D. To regulate power-factor correction
Answer: B. To provide overcurrent protection
Rationale: A circuit breaker opens the circuit when current exceeds its
rated value under applicable operating conditions. This protects
conductors and equipment from damage caused by excessive current.
4. Which conductor normally carries current back to the source on a
120-volt branch circuit?
A. Equipment grounding conductor
B. Grounding electrode conductor
C. Grounded conductor
D. Bonding jumper
Answer: C. Grounded conductor
Rationale: The grounded conductor, commonly called the neutral,
provides the normal return path for current from a 120-volt load back
to the source. The equipment grounding conductor normally carries
current only during a fault condition.
, 5. What is the purpose of an equipment grounding conductor?
A. To carry normal load current
B. To provide a low-impedance fault-current path
C. To increase circuit voltage
D. To replace the grounded conductor
Answer: B. To provide a low-impedance fault-current path
Rationale: The equipment grounding conductor connects normally
non-current-carrying metal parts to the grounding system. During a
fault, it provides a path that helps fault current return to the source
and operate the overcurrent protective device.
6. Which device is specifically designed to provide protection against
electric shock caused by certain ground-fault conditions?
A. AFCI
B. GFCI
C. Disconnect switch
D. Surge protector
Answer: B. GFCI
Rationale: A ground-fault circuit interrupter monitors current leaving
and returning through the circuit conductors. When it detects an
Examination (Technical 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) in
residential electrical installations?
A. To establish electrical utility rates
B. To provide practical safeguards for persons and property from
electrical hazards
C. To determine the cost of electrical labor
D. To regulate the sale of electrical appliances
Answer: B. To provide practical safeguards for persons and property
from electrical hazards
Rationale: The NEC establishes minimum requirements intended to
protect people and property from hazards arising from the use of
electricity. It addresses wiring methods, equipment installation,
,overcurrent protection, grounding, and many other safety
considerations.
2. In a typical 120/240-volt single-phase residential system, what is
the voltage measured between the two ungrounded conductors?
A. 120 volts
B. 208 volts
C. 240 volts
D. 480 volts
Answer: C. 240 volts
Rationale: A typical residential single-phase service has two
ungrounded conductors, each approximately 120 volts to the neutral.
Because they are opposite in phase, the voltage between them is
approximately 240 volts.
3. What is the function of a circuit breaker in a residential branch
circuit?
A. To increase circuit voltage
B. To provide overcurrent protection
,C. To eliminate the need for grounding
D. To regulate power-factor correction
Answer: B. To provide overcurrent protection
Rationale: A circuit breaker opens the circuit when current exceeds its
rated value under applicable operating conditions. This protects
conductors and equipment from damage caused by excessive current.
4. Which conductor normally carries current back to the source on a
120-volt branch circuit?
A. Equipment grounding conductor
B. Grounding electrode conductor
C. Grounded conductor
D. Bonding jumper
Answer: C. Grounded conductor
Rationale: The grounded conductor, commonly called the neutral,
provides the normal return path for current from a 120-volt load back
to the source. The equipment grounding conductor normally carries
current only during a fault condition.
, 5. What is the purpose of an equipment grounding conductor?
A. To carry normal load current
B. To provide a low-impedance fault-current path
C. To increase circuit voltage
D. To replace the grounded conductor
Answer: B. To provide a low-impedance fault-current path
Rationale: The equipment grounding conductor connects normally
non-current-carrying metal parts to the grounding system. During a
fault, it provides a path that helps fault current return to the source
and operate the overcurrent protective device.
6. Which device is specifically designed to provide protection against
electric shock caused by certain ground-fault conditions?
A. AFCI
B. GFCI
C. Disconnect switch
D. Surge protector
Answer: B. GFCI
Rationale: A ground-fault circuit interrupter monitors current leaving
and returning through the circuit conductors. When it detects an
