NORTH CAROLINA RESIDENTIAL
SINGLE-FAMILY DWELLING
ELECTRICAL CONTRACTOR (SP-SFD)
COMPREHENSIVE EXAM QUESTIONS
AND CORRECT ANSWERS WITH
EXPLANATIONS
1. According to NEC Table 310.12, what is the minimum size copper service-entrance
conductor required for a 200-ampere, 120/240-volt, single-phase, 3-wire residential service?
A. 1/0 AWG
B. 3/0 AWG
C. 2/0 AWG
D. 4/0 AWG
Answer: C
Conceptual Explanation: NEC Table 310.12 allows 2/0 AWG copper for a 200A residential
service/feeder under specific conditions (120/240V, 3-wire, single-phase).
2. What is the calculated load for one 12 kW household electric range in a single-family
dwelling?
A. 8 kW
,B. 12 kW
C. 9.6 kW
D. 10 kW
Answer: A
Conceptual Explanation: Table 220.55, Column C states that for one range not over 12
kW, the demand load is 8 kW.
3. In a residential kitchen, what is the minimum number of 20-ampere small-appliance branch
circuits required to serve countertop surfaces?
A. 2
B. 1
C. 3
D. 4
Answer: A
Conceptual Explanation: NEC 210.11(C)(1) and 210.52(B) require at least two 20-ampere
small-appliance branch circuits for the kitchen countertop area.
4. A 120-volt, 20-ampere branch circuit supplies a residential bathroom. Which of the
following is true?
A. The circuit can also feed lighting in the bathroom if it only serves that one bathroom.
B. The circuit must only feed the receptacle and cannot feed any other loads.
, C. Both A and C are correct.
D. The circuit can feed receptacles in multiple bathrooms but no lighting.
Answer: C
Conceptual Explanation: NEC 210.11(C)(3) allows a 20A bathroom circuit to feed all
equipment in one bathroom, OR only receptacles in multiple bathrooms.
5. What is the minimum burial depth for a 120V, 20A GFCI-protected residential branch circuit
using UF cable under a driveway?
A. 6 inches
B. 18 inches
C. 12 inches
D. 24 inches
Answer: C
Conceptual Explanation: Table 300.5, Column 4 allows 12 inches for residential branch
circuits rated 120V or less with GFCI protection and a max overcurrent protection of 20A.
6. Where a service mast is used for the support of service-drop conductors, it must be of
adequate strength or be supported by:
A. Braces or guys
B. Roof decking only
C. Standard electrical metallic tubing
SINGLE-FAMILY DWELLING
ELECTRICAL CONTRACTOR (SP-SFD)
COMPREHENSIVE EXAM QUESTIONS
AND CORRECT ANSWERS WITH
EXPLANATIONS
1. According to NEC Table 310.12, what is the minimum size copper service-entrance
conductor required for a 200-ampere, 120/240-volt, single-phase, 3-wire residential service?
A. 1/0 AWG
B. 3/0 AWG
C. 2/0 AWG
D. 4/0 AWG
Answer: C
Conceptual Explanation: NEC Table 310.12 allows 2/0 AWG copper for a 200A residential
service/feeder under specific conditions (120/240V, 3-wire, single-phase).
2. What is the calculated load for one 12 kW household electric range in a single-family
dwelling?
A. 8 kW
,B. 12 kW
C. 9.6 kW
D. 10 kW
Answer: A
Conceptual Explanation: Table 220.55, Column C states that for one range not over 12
kW, the demand load is 8 kW.
3. In a residential kitchen, what is the minimum number of 20-ampere small-appliance branch
circuits required to serve countertop surfaces?
A. 2
B. 1
C. 3
D. 4
Answer: A
Conceptual Explanation: NEC 210.11(C)(1) and 210.52(B) require at least two 20-ampere
small-appliance branch circuits for the kitchen countertop area.
4. A 120-volt, 20-ampere branch circuit supplies a residential bathroom. Which of the
following is true?
A. The circuit can also feed lighting in the bathroom if it only serves that one bathroom.
B. The circuit must only feed the receptacle and cannot feed any other loads.
, C. Both A and C are correct.
D. The circuit can feed receptacles in multiple bathrooms but no lighting.
Answer: C
Conceptual Explanation: NEC 210.11(C)(3) allows a 20A bathroom circuit to feed all
equipment in one bathroom, OR only receptacles in multiple bathrooms.
5. What is the minimum burial depth for a 120V, 20A GFCI-protected residential branch circuit
using UF cable under a driveway?
A. 6 inches
B. 18 inches
C. 12 inches
D. 24 inches
Answer: C
Conceptual Explanation: Table 300.5, Column 4 allows 12 inches for residential branch
circuits rated 120V or less with GFCI protection and a max overcurrent protection of 20A.
6. Where a service mast is used for the support of service-drop conductors, it must be of
adequate strength or be supported by:
A. Braces or guys
B. Roof decking only
C. Standard electrical metallic tubing
