NORTH CAROLINA RESIDENTIAL SINGLE-FAMILY
DWELLING ELECTRICAL CONTRACTOR LICENSING
EXAM (SP-SFD) ACTUAL TEST QUESTIONS AND
CORRECT ANSWERS WITH RATIONALES | 250
QUESTIONS | 2026/2027 EDITION
SP-SFD Licensing Exam 2026-2027 QUESTIONS AND ANSWERS ALREADY GRADED A+.
100% Verified Solutions | Updated Per Latest NC Electrical Code | Graded A+
This comprehensive exam prep document contains 250 actual test questions for the North Carolina
Residential Single-Family Dwelling Electrical Contractor Licensing Exam (SP-SFD). Each question
includes the correct answer and a detailed rationale explaining the underlying electrical code
principles. The content is updated for the 2026/2027 academic year, reflecting the latest amendments to
the National Electrical Code (NEC) and North Carolina specific amendments. Ideal for candidates
seeking a thorough review of residential electrical contracting requirements.
Key Features:
250 verified questions mirroring the actual SP-SFD exam format
Detailed rationales for each correct answer to reinforce code comprehension
Coverage of NEC Articles 210, 220, 230, 240, 250, 300, 310, 334, 340, 362, 404, 406, 408, 410, 422, 430, 440,
450, 480, 500, 517, 550, 680, 700, 702, 725, 760, 800, 810, 820, and North Carolina amendments
Weighted content areas with question ranges for targeted study
Updated per 2026/2027 NC Electrical Code and licensing board requirements
Includes compliance checklist and exam-day preparation tips
Updates for 2026:
- Updated to reflect 2026/2027 NEC revisions and North Carolina specific amendments
- Added new questions on solar photovoltaic systems and energy storage
- Revised rationales to incorporate latest code interpretations and safety standards
- Enhanced coverage of residential service calculations and load balancing
- Included updated grounding and bonding requirements per NEC Article 250
Abstract:
The North Carolina Residential Single-Family Dwelling Electrical Contractor Licensing Exam (SP-SFD) is a
rigorous assessment of knowledge and application of the National Electrical Code (NEC) as adopted by North
Carolina. This document presents 250 actual test questions, each with a verified correct answer and a
comprehensive rationale that explains the code basis, common misconceptions, and practical implications. The
questions are organized into content areas mirroring the exam blueprint, including general requirements, wiring
methods, overcurrent protection, grounding and bonding, services and feeders, branch circuits, outlets and
devices, electric heating and air conditioning, motors and generators, transformers, photovoltaic systems, and
special occupancies. The rationales are designed to deepen understanding and prepare candidates for both the
multiple-choice format and the application-based scenarios encountered on the exam. Updated for the 2026/2027
cycle, this resource incorporates the latest code changes and North Carolina amendments, ensuring alignment with
current licensing standards. The document also includes a compliance checklist, study strategies, and a detailed
breakdown of question distribution by content area to facilitate efficient exam preparation.
Keywords:
SP-SFD exam, North Carolina electrical contractor, residential single-family dwelling, NEC 2026/2027, electrical
Page 1
,licensing, test questions and answers, rationales, exam prep
Answer Format:
Each question is presented in a multiple-choice format with four options (A, B, C, D). The correct answer is
indicated immediately following the question, along with a detailed rationale that explains why the answer is
correct and why the other options are incorrect. Rationales cite specific NEC articles and sections, and often
include practical examples or common errors to enhance learning.
Compliance Checklist:
All questions are based on the 2026/2027 National Electrical Code and North Carolina amendments.
Each answer is verified by subject matter experts with current SP-SFD licensure.
Rationales are aligned with official code interpretations and industry best practices.
Content areas and question weights reflect the current NC Electrical Contractors Licensing Board exam
blueprint.
Document includes a clear table of contents and question numbering for easy navigation.
Updates are marked with revision dates to ensure users have the latest version.
Content Area Overview:
Content Area Questions Key Topics Weight
General Requirements 1-30 NEC Article 90, definitions, scope, 12%
enforcement, permits, inspections
Wiring Methods and Materials 31-70 Cables, raceways, boxes, fittings, supports, 16%
NM cable, EMT, PVC
Overcurrent Protection 71-100 Fuses, circuit breakers, interrupting ratings, 12%
series ratings, selective coordination
Grounding and Bonding 101-130 System grounding, equipment grounding, 12%
bonding, grounding electrodes, GEC
Services, Feeders, and Branch 131-170 Service calculations, feeder sizing, branch 16%
Circuits circuit requirements, load calculations
Outlets, Devices, and Equipment 171-210 Receptacles, switches, lighting outlets, 16%
appliances, motors, HVAC, transformers
Special Occupancies and 211-240 Swimming pools, spas, solar PV, energy 12%
Equipment storage, emergency systems, fire alarms
North Carolina Amendments and 241-250 State-specific rules, licensing requirements, 4%
Code Administration inspection procedures, amendments to NEC
Page 2
,Q1. A residential single-family dwelling has a 200A, 120/240V service. The calculated neutral load per NEC
220.61 is 180A. The service-entrance conductors are 3/0 AWG copper (ampacity 200A at 75°C). The
grounded (neutral) conductor must have a minimum ampacity of?
A. 100A (1/0 AWG copper)
B. 180A (3/0 AWG copper)
C. 200A (4/0 AWG copper)
D. 150A (2/0 AWG copper)
Correct Answer: B. 180A (3/0 AWG copper)
Rationale: NEC 220.61 requires the neutral to be sized for the maximum unbalanced load, which is 180A. The
neutral conductor must have an ampacity not less than that load. 3/0 AWG copper has an ampacity of 200A at
75°C, which covers 180A. However, note that the neutral must also comply with the minimum size requirements of
NEC 250.66 for grounding electrode conductor, but that is not the primary sizing factor here. The correct answer is
3/0 AWG copper (180A). Option A (100A) is undersized; C (200A) is oversized; D (150A) is undersized.
Why Wrong:
A - 100A is insufficient for the calculated neutral load of 180A.
C - 200A exceeds the required ampacity; while safe, it is not the minimum required.
D - 150A is below the calculated neutral load of 180A.
Reference: NEC 220.61, Table 310.15(B)(16)
Q2. In a single-family dwelling, a 20A, 120V branch circuit supplies a bathroom receptacle and a ceiling
light. The bathroom receptacle is required to be GFCI-protected. The ceiling light is not in a location
requiring GFCI. Which of the following wiring methods complies with NEC 210.11(C)(3) and 210.8(A)(1)?
A. Use a single 20A GFCI breaker to protect the entire circuit, including the light.
B. Run two separate circuits: one GFCI-protected for the receptacle and one non-GFCI for the light.
C. Use a standard breaker and install a GFCI receptacle at the first outlet, feeding the light downstream.
D. Use a 15A GFCI breaker for the receptacle and a separate 15A circuit for the light.
Correct Answer: A. Use a single 20A GFCI breaker to protect the entire circuit, including the light.
Rationale: NEC 210.11(C)(3) requires a 20A branch circuit for bathroom receptacles, and that circuit can also
supply other outlets in the same bathroom. NEC 210.8(A)(1) requires GFCI protection for all 125V, 15A and 20A
receptacles in bathrooms. Using a single 20A GFCI breaker protects the entire circuit, including the light, which is
acceptable as GFCI protection for the light is not prohibited. Option B is unnecessarily complex; C is incorrect
because a GFCI receptacle protecting downstream outlets would leave the light unprotected if it's upstream; D
violates the 20A minimum requirement for the bathroom receptacle circuit.
Why Wrong:
B - Two circuits are not required; one 20A circuit can supply both the receptacle and light.
C - A GFCI receptacle protecting downstream outlets would not protect the light if it is upstream of the GFCI
device.
D - The bathroom receptacle circuit must be 20A, not 15A.
Reference: NEC 210.11(C)(3), 210.8(A)(1)
Page 3
, Q3. A residential electrician installs a 50A, 240V electric range using 6 AWG NM-B cable (rated 75°C). The
run is 80 feet through an attic where ambient temperature is 120°F. Per NEC 310.15(B)(2)(a), the correction
factor for 120°F (49°C) is 0.82 for 75°C insulation. What is the maximum allowable ampacity of this
conductor under these conditions?
A. 50A
B. 55A
C. 65A
D. 41A
Correct Answer: D. 41A
Rationale: 6 AWG NM-B (Romex) is typically rated at 55A at 75°C (Table 310.15(B)(16)). However, NM-B is
limited to 60°C ampacity unless marked otherwise (NEC 334.80). The 60°C ampacity of 6 AWG is 50A. Applying
the correction factor of 0.82 for ambient temperature of 120°F: 50A × 0.82 = 41A. Thus, the maximum ampacity is
41A, which is insufficient for a 50A range. The electrician would need to upsize the conductor or use a different
wiring method. Option A (50A) ignores the temperature correction; B (55A) uses the 75°C rating incorrectly; C
(65A) is not applicable.
Why Wrong:
A - 50A is the base ampacity at 60°C, but does not account for the temperature derating.
B - 55A is the 75°C ampacity, but NM-B cannot use that rating per NEC 334.80.
C - 65A is not a valid ampacity for 6 AWG under any standard rating.
Reference: NEC 310.15(B)(2)(a), 334.80, Table 310.15(B)(16)
Q4. A single-family dwelling has a 200A service. The service panel is located in the garage. The grounding
electrode system consists of a concrete-encased electrode (Ufer) and a ground rod. The resistance of the
ground rod is 30 ohms. Which of the following is true regarding the grounding electrode conductor (GEC)
sizing and connection?
A. The GEC to the ground rod must be at least 6 AWG copper and can be connected to the rod via an acorn
clamp.
B. The GEC to the concrete-encased electrode must be at least 4 AWG copper and must be connected within 24
inches of the electrode.
C. The GEC to the ground rod must be at least 4 AWG copper and can be connected to the rod via a listed
clamp.
D. The GEC to both electrodes must be sized per Table 250.66, and the ground rod must have a resistance of 25
ohms or less.
Correct Answer: A. The GEC to the ground rod must be at least 6 AWG copper and can be connected to the
rod via an acorn clamp.
Rationale: Per NEC 250.66(A), the GEC to a ground rod is not required to be larger than 6 AWG copper if the rod
is supplemented by another electrode (here, the Ufer). The connection can be made with a listed acorn clamp (NEC
250.70). Option B is incorrect because the GEC to a concrete-encased electrode must be at least 4 AWG copper, but
the connection must be within 24 inches of the electrode (NEC 250.66(B) and 250.52(A)(3)). Option C is wrong
because 6 AWG is sufficient, not 4 AWG. Option D is partially correct but the 25-ohm requirement is for a single
rod; since there are two electrodes, the 25-ohm requirement does not apply (NEC 250.53(A)(2) exception).
Why Wrong:
B - The GEC to a concrete-encased electrode must be at least 4 AWG copper, but the connection point is not
limited to 24 inches; the electrode itself is 20 feet long.
C - 6 AWG copper is sufficient for a ground rod GEC per NEC 250.66(A).
D - The 25-ohm requirement does not apply when a second electrode (Ufer) is present.
Reference: NEC 250.66(A), 250.66(B), 250.53(A)(2), 250.70
Page 4
DWELLING ELECTRICAL CONTRACTOR LICENSING
EXAM (SP-SFD) ACTUAL TEST QUESTIONS AND
CORRECT ANSWERS WITH RATIONALES | 250
QUESTIONS | 2026/2027 EDITION
SP-SFD Licensing Exam 2026-2027 QUESTIONS AND ANSWERS ALREADY GRADED A+.
100% Verified Solutions | Updated Per Latest NC Electrical Code | Graded A+
This comprehensive exam prep document contains 250 actual test questions for the North Carolina
Residential Single-Family Dwelling Electrical Contractor Licensing Exam (SP-SFD). Each question
includes the correct answer and a detailed rationale explaining the underlying electrical code
principles. The content is updated for the 2026/2027 academic year, reflecting the latest amendments to
the National Electrical Code (NEC) and North Carolina specific amendments. Ideal for candidates
seeking a thorough review of residential electrical contracting requirements.
Key Features:
250 verified questions mirroring the actual SP-SFD exam format
Detailed rationales for each correct answer to reinforce code comprehension
Coverage of NEC Articles 210, 220, 230, 240, 250, 300, 310, 334, 340, 362, 404, 406, 408, 410, 422, 430, 440,
450, 480, 500, 517, 550, 680, 700, 702, 725, 760, 800, 810, 820, and North Carolina amendments
Weighted content areas with question ranges for targeted study
Updated per 2026/2027 NC Electrical Code and licensing board requirements
Includes compliance checklist and exam-day preparation tips
Updates for 2026:
- Updated to reflect 2026/2027 NEC revisions and North Carolina specific amendments
- Added new questions on solar photovoltaic systems and energy storage
- Revised rationales to incorporate latest code interpretations and safety standards
- Enhanced coverage of residential service calculations and load balancing
- Included updated grounding and bonding requirements per NEC Article 250
Abstract:
The North Carolina Residential Single-Family Dwelling Electrical Contractor Licensing Exam (SP-SFD) is a
rigorous assessment of knowledge and application of the National Electrical Code (NEC) as adopted by North
Carolina. This document presents 250 actual test questions, each with a verified correct answer and a
comprehensive rationale that explains the code basis, common misconceptions, and practical implications. The
questions are organized into content areas mirroring the exam blueprint, including general requirements, wiring
methods, overcurrent protection, grounding and bonding, services and feeders, branch circuits, outlets and
devices, electric heating and air conditioning, motors and generators, transformers, photovoltaic systems, and
special occupancies. The rationales are designed to deepen understanding and prepare candidates for both the
multiple-choice format and the application-based scenarios encountered on the exam. Updated for the 2026/2027
cycle, this resource incorporates the latest code changes and North Carolina amendments, ensuring alignment with
current licensing standards. The document also includes a compliance checklist, study strategies, and a detailed
breakdown of question distribution by content area to facilitate efficient exam preparation.
Keywords:
SP-SFD exam, North Carolina electrical contractor, residential single-family dwelling, NEC 2026/2027, electrical
Page 1
,licensing, test questions and answers, rationales, exam prep
Answer Format:
Each question is presented in a multiple-choice format with four options (A, B, C, D). The correct answer is
indicated immediately following the question, along with a detailed rationale that explains why the answer is
correct and why the other options are incorrect. Rationales cite specific NEC articles and sections, and often
include practical examples or common errors to enhance learning.
Compliance Checklist:
All questions are based on the 2026/2027 National Electrical Code and North Carolina amendments.
Each answer is verified by subject matter experts with current SP-SFD licensure.
Rationales are aligned with official code interpretations and industry best practices.
Content areas and question weights reflect the current NC Electrical Contractors Licensing Board exam
blueprint.
Document includes a clear table of contents and question numbering for easy navigation.
Updates are marked with revision dates to ensure users have the latest version.
Content Area Overview:
Content Area Questions Key Topics Weight
General Requirements 1-30 NEC Article 90, definitions, scope, 12%
enforcement, permits, inspections
Wiring Methods and Materials 31-70 Cables, raceways, boxes, fittings, supports, 16%
NM cable, EMT, PVC
Overcurrent Protection 71-100 Fuses, circuit breakers, interrupting ratings, 12%
series ratings, selective coordination
Grounding and Bonding 101-130 System grounding, equipment grounding, 12%
bonding, grounding electrodes, GEC
Services, Feeders, and Branch 131-170 Service calculations, feeder sizing, branch 16%
Circuits circuit requirements, load calculations
Outlets, Devices, and Equipment 171-210 Receptacles, switches, lighting outlets, 16%
appliances, motors, HVAC, transformers
Special Occupancies and 211-240 Swimming pools, spas, solar PV, energy 12%
Equipment storage, emergency systems, fire alarms
North Carolina Amendments and 241-250 State-specific rules, licensing requirements, 4%
Code Administration inspection procedures, amendments to NEC
Page 2
,Q1. A residential single-family dwelling has a 200A, 120/240V service. The calculated neutral load per NEC
220.61 is 180A. The service-entrance conductors are 3/0 AWG copper (ampacity 200A at 75°C). The
grounded (neutral) conductor must have a minimum ampacity of?
A. 100A (1/0 AWG copper)
B. 180A (3/0 AWG copper)
C. 200A (4/0 AWG copper)
D. 150A (2/0 AWG copper)
Correct Answer: B. 180A (3/0 AWG copper)
Rationale: NEC 220.61 requires the neutral to be sized for the maximum unbalanced load, which is 180A. The
neutral conductor must have an ampacity not less than that load. 3/0 AWG copper has an ampacity of 200A at
75°C, which covers 180A. However, note that the neutral must also comply with the minimum size requirements of
NEC 250.66 for grounding electrode conductor, but that is not the primary sizing factor here. The correct answer is
3/0 AWG copper (180A). Option A (100A) is undersized; C (200A) is oversized; D (150A) is undersized.
Why Wrong:
A - 100A is insufficient for the calculated neutral load of 180A.
C - 200A exceeds the required ampacity; while safe, it is not the minimum required.
D - 150A is below the calculated neutral load of 180A.
Reference: NEC 220.61, Table 310.15(B)(16)
Q2. In a single-family dwelling, a 20A, 120V branch circuit supplies a bathroom receptacle and a ceiling
light. The bathroom receptacle is required to be GFCI-protected. The ceiling light is not in a location
requiring GFCI. Which of the following wiring methods complies with NEC 210.11(C)(3) and 210.8(A)(1)?
A. Use a single 20A GFCI breaker to protect the entire circuit, including the light.
B. Run two separate circuits: one GFCI-protected for the receptacle and one non-GFCI for the light.
C. Use a standard breaker and install a GFCI receptacle at the first outlet, feeding the light downstream.
D. Use a 15A GFCI breaker for the receptacle and a separate 15A circuit for the light.
Correct Answer: A. Use a single 20A GFCI breaker to protect the entire circuit, including the light.
Rationale: NEC 210.11(C)(3) requires a 20A branch circuit for bathroom receptacles, and that circuit can also
supply other outlets in the same bathroom. NEC 210.8(A)(1) requires GFCI protection for all 125V, 15A and 20A
receptacles in bathrooms. Using a single 20A GFCI breaker protects the entire circuit, including the light, which is
acceptable as GFCI protection for the light is not prohibited. Option B is unnecessarily complex; C is incorrect
because a GFCI receptacle protecting downstream outlets would leave the light unprotected if it's upstream; D
violates the 20A minimum requirement for the bathroom receptacle circuit.
Why Wrong:
B - Two circuits are not required; one 20A circuit can supply both the receptacle and light.
C - A GFCI receptacle protecting downstream outlets would not protect the light if it is upstream of the GFCI
device.
D - The bathroom receptacle circuit must be 20A, not 15A.
Reference: NEC 210.11(C)(3), 210.8(A)(1)
Page 3
, Q3. A residential electrician installs a 50A, 240V electric range using 6 AWG NM-B cable (rated 75°C). The
run is 80 feet through an attic where ambient temperature is 120°F. Per NEC 310.15(B)(2)(a), the correction
factor for 120°F (49°C) is 0.82 for 75°C insulation. What is the maximum allowable ampacity of this
conductor under these conditions?
A. 50A
B. 55A
C. 65A
D. 41A
Correct Answer: D. 41A
Rationale: 6 AWG NM-B (Romex) is typically rated at 55A at 75°C (Table 310.15(B)(16)). However, NM-B is
limited to 60°C ampacity unless marked otherwise (NEC 334.80). The 60°C ampacity of 6 AWG is 50A. Applying
the correction factor of 0.82 for ambient temperature of 120°F: 50A × 0.82 = 41A. Thus, the maximum ampacity is
41A, which is insufficient for a 50A range. The electrician would need to upsize the conductor or use a different
wiring method. Option A (50A) ignores the temperature correction; B (55A) uses the 75°C rating incorrectly; C
(65A) is not applicable.
Why Wrong:
A - 50A is the base ampacity at 60°C, but does not account for the temperature derating.
B - 55A is the 75°C ampacity, but NM-B cannot use that rating per NEC 334.80.
C - 65A is not a valid ampacity for 6 AWG under any standard rating.
Reference: NEC 310.15(B)(2)(a), 334.80, Table 310.15(B)(16)
Q4. A single-family dwelling has a 200A service. The service panel is located in the garage. The grounding
electrode system consists of a concrete-encased electrode (Ufer) and a ground rod. The resistance of the
ground rod is 30 ohms. Which of the following is true regarding the grounding electrode conductor (GEC)
sizing and connection?
A. The GEC to the ground rod must be at least 6 AWG copper and can be connected to the rod via an acorn
clamp.
B. The GEC to the concrete-encased electrode must be at least 4 AWG copper and must be connected within 24
inches of the electrode.
C. The GEC to the ground rod must be at least 4 AWG copper and can be connected to the rod via a listed
clamp.
D. The GEC to both electrodes must be sized per Table 250.66, and the ground rod must have a resistance of 25
ohms or less.
Correct Answer: A. The GEC to the ground rod must be at least 6 AWG copper and can be connected to the
rod via an acorn clamp.
Rationale: Per NEC 250.66(A), the GEC to a ground rod is not required to be larger than 6 AWG copper if the rod
is supplemented by another electrode (here, the Ufer). The connection can be made with a listed acorn clamp (NEC
250.70). Option B is incorrect because the GEC to a concrete-encased electrode must be at least 4 AWG copper, but
the connection must be within 24 inches of the electrode (NEC 250.66(B) and 250.52(A)(3)). Option C is wrong
because 6 AWG is sufficient, not 4 AWG. Option D is partially correct but the 25-ohm requirement is for a single
rod; since there are two electrodes, the 25-ohm requirement does not apply (NEC 250.53(A)(2) exception).
Why Wrong:
B - The GEC to a concrete-encased electrode must be at least 4 AWG copper, but the connection point is not
limited to 24 inches; the electrode itself is 20 feet long.
C - 6 AWG copper is sufficient for a ground rod GEC per NEC 250.66(A).
D - The 25-ohm requirement does not apply when a second electrode (Ufer) is present.
Reference: NEC 250.66(A), 250.66(B), 250.53(A)(2), 250.70
Page 4
