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North Carolina Residential Single-Family Dwelling
Electrical Contractor License Exam (SP-SFD) | Latest
Verified Questions and Detailed Answers
OVERVIEW DESCRIPTION:
This comprehensive set of unique multiple-choice questions is designed specifically for the
North Carolina Residential Single-Family Dwelling Electrical Contractor License Exam (SP-
SFD). The questions cover all critical knowledge areas required for the exam, including the
National Electrical Code (NEC), North Carolina state-specific laws and amendments,
electrical theory, load calculations, wiring methods, grounding and bonding, safety
practices, and business/project management fundamentals. Each question is presented in a
consistent format with four answer choices, followed by the correct answer and a concise,
expert rationale that provides clear, code-based justification to reinforce understanding.
I. NEC General Requirements, Definitions & Fundamentals
QUESTION 1
In the NEC, what is the primary purpose of a grounding conductor?
A) To provide a return path for normal load current
B) To serve as a current-carrying conductor under normal conditions
C) To open an overcurrent protection device during a fault event
D) To connect non-current-carrying metal parts of electrical equipment to the earth
CORRECT ANSWER: C
EXPERT RATIONALE: An equipment grounding conductor provides a low-impedance
path for fault current to return to the source, which allows the overcurrent device to
open quickly and clear the fault, thereby protecting personnel from electric shock.
,2|Page
QUESTION 2
Which NEC article covers the specific requirements for electrical installations in one-
family dwellings?
A) Article 210
B) Article 220
C) Article 230
D) Article 334
CORRECT ANSWER: C
EXPERT RATIONALE: Article 230 covers services, which are the conductors and
equipment for delivering electricity from the utility to the wiring system of the premises,
including one-family dwellings.
QUESTION 3
In the context of the NEC, what is the definition of a "qualified person"?
A) A licensed electrical contractor
B) A person who has skills and knowledge related to the construction and operation of
electrical equipment and has received safety training to identify and avoid hazards
C) Any journeyman electrician
D) An employee of a utility company
CORRECT ANSWER: B
EXPERT RATIONALE: The NEC defines a qualified person based on their knowledge and
training, not solely on their license or job title, as they must be able to recognize and
avoid the hazards involved with electrical equipment.
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QUESTION 4
A single-family dwelling is supplied by a 120/240-volt, single-phase service. Which
conductor is required to be identified by a white or gray finish?
A) The ungrounded conductor connected to the "B" phase
B) The equipment grounding conductor
C) The grounded circuit conductor
D) The high-leg conductor
CORRECT ANSWER: C
EXPERT RATIONALE: The grounded conductor, often called the neutral, must be
identified by a continuous white or gray outer finish or by three continuous white or
gray stripes on insulation that is not green.
QUESTION 5
What is the minimum headroom required for a working space that contains electrical
equipment operating at 600 volts or less and that requires examination, adjustment, or
maintenance while energized?
A) 3 feet
B) 6 feet 6 inches
C) 7 feet
D) 8 feet
CORRECT ANSWER: B
EXPERT RATIONALE: NEC 110.26(E) requires a minimum headroom of 6 feet 6 inches or
the height of the equipment, whichever is greater, for working spaces to ensure safe
access and egress.
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QUESTION 6
In the NEC, the term "ampacity" is defined as the maximum current, in amperes, that a
conductor can carry continuously under the conditions of use without exceeding its:
A) Voltage rating
B) Insulation resistance
C) Temperature rating
D) Mechanical strength limit
CORRECT ANSWER: C
EXPERT RATIONALE: Ampacity is fundamentally tied to the temperature rating of the
conductor's insulation. Exceeding the ampacity will cause the conductor to overheat,
damaging the insulation and creating a fire hazard.
QUESTION 7
Where in the NEC would you find the definition of "Dwelling Unit"?
A) Annex A
B) Article 100
C) Article 90
D) Chapter 9, Table 1
CORRECT ANSWER: B
EXPERT RATIONALE: Article 100 of the NEC contains all the essential definitions used
throughout the code, including the definition of a dwelling unit, which is a single unit
providing complete and independent living facilities.
North Carolina Residential Single-Family Dwelling
Electrical Contractor License Exam (SP-SFD) | Latest
Verified Questions and Detailed Answers
OVERVIEW DESCRIPTION:
This comprehensive set of unique multiple-choice questions is designed specifically for the
North Carolina Residential Single-Family Dwelling Electrical Contractor License Exam (SP-
SFD). The questions cover all critical knowledge areas required for the exam, including the
National Electrical Code (NEC), North Carolina state-specific laws and amendments,
electrical theory, load calculations, wiring methods, grounding and bonding, safety
practices, and business/project management fundamentals. Each question is presented in a
consistent format with four answer choices, followed by the correct answer and a concise,
expert rationale that provides clear, code-based justification to reinforce understanding.
I. NEC General Requirements, Definitions & Fundamentals
QUESTION 1
In the NEC, what is the primary purpose of a grounding conductor?
A) To provide a return path for normal load current
B) To serve as a current-carrying conductor under normal conditions
C) To open an overcurrent protection device during a fault event
D) To connect non-current-carrying metal parts of electrical equipment to the earth
CORRECT ANSWER: C
EXPERT RATIONALE: An equipment grounding conductor provides a low-impedance
path for fault current to return to the source, which allows the overcurrent device to
open quickly and clear the fault, thereby protecting personnel from electric shock.
,2|Page
QUESTION 2
Which NEC article covers the specific requirements for electrical installations in one-
family dwellings?
A) Article 210
B) Article 220
C) Article 230
D) Article 334
CORRECT ANSWER: C
EXPERT RATIONALE: Article 230 covers services, which are the conductors and
equipment for delivering electricity from the utility to the wiring system of the premises,
including one-family dwellings.
QUESTION 3
In the context of the NEC, what is the definition of a "qualified person"?
A) A licensed electrical contractor
B) A person who has skills and knowledge related to the construction and operation of
electrical equipment and has received safety training to identify and avoid hazards
C) Any journeyman electrician
D) An employee of a utility company
CORRECT ANSWER: B
EXPERT RATIONALE: The NEC defines a qualified person based on their knowledge and
training, not solely on their license or job title, as they must be able to recognize and
avoid the hazards involved with electrical equipment.
,3|Page
QUESTION 4
A single-family dwelling is supplied by a 120/240-volt, single-phase service. Which
conductor is required to be identified by a white or gray finish?
A) The ungrounded conductor connected to the "B" phase
B) The equipment grounding conductor
C) The grounded circuit conductor
D) The high-leg conductor
CORRECT ANSWER: C
EXPERT RATIONALE: The grounded conductor, often called the neutral, must be
identified by a continuous white or gray outer finish or by three continuous white or
gray stripes on insulation that is not green.
QUESTION 5
What is the minimum headroom required for a working space that contains electrical
equipment operating at 600 volts or less and that requires examination, adjustment, or
maintenance while energized?
A) 3 feet
B) 6 feet 6 inches
C) 7 feet
D) 8 feet
CORRECT ANSWER: B
EXPERT RATIONALE: NEC 110.26(E) requires a minimum headroom of 6 feet 6 inches or
the height of the equipment, whichever is greater, for working spaces to ensure safe
access and egress.
, 4|Page
QUESTION 6
In the NEC, the term "ampacity" is defined as the maximum current, in amperes, that a
conductor can carry continuously under the conditions of use without exceeding its:
A) Voltage rating
B) Insulation resistance
C) Temperature rating
D) Mechanical strength limit
CORRECT ANSWER: C
EXPERT RATIONALE: Ampacity is fundamentally tied to the temperature rating of the
conductor's insulation. Exceeding the ampacity will cause the conductor to overheat,
damaging the insulation and creating a fire hazard.
QUESTION 7
Where in the NEC would you find the definition of "Dwelling Unit"?
A) Annex A
B) Article 100
C) Article 90
D) Chapter 9, Table 1
CORRECT ANSWER: B
EXPERT RATIONALE: Article 100 of the NEC contains all the essential definitions used
throughout the code, including the definition of a dwelling unit, which is a single unit
providing complete and independent living facilities.
