NORTH CAROLINA RESIDENTIAL
SINGLE-FAMILY DWELLING
ELECTRICAL CONTRACTOR EXAM
QUESTIONS AND CORRECT ANSWERS
WITH EXPLANATIONS
1. A 200-ampere single-phase residential service is being installed using 2/0 AWG copper
ungrounded conductors. What is the minimum size required for the copper grounding
electrode conductor to a concrete-encased electrode?
A. 6 AWG
B. 4 AWG
C. 2 AWG
D. 1/0 AWG
Answer: A
Conceptual Explanation: According to NEC 250.66(B), if the grounding electrode
conductor is connected to a concrete-encased electrode, that portion of the conductor that
is the sole connection to the grounding electrode shall not be required to be larger than 4
AWG copper; however, many residential codes specify 4 or 6, and specifically for concrete-
encased, 6 AWG is the max required for the electrode itself.
,2. In a residential kitchen, what is the maximum distance allowed between receptacles along
the wall line of a countertop space?
A. 2 feet
B. 4 feet
C. 6 feet
D. 12 feet
Answer: B
Conceptual Explanation: NEC 210.52(C)(1) states that receptacles shall be installed so
that no point along the wall line is more than 24 inches (2 feet) measured horizontally from
a receptacle outlet. This effectively means a maximum of 4 feet between receptacles.
3. What is the demand load for one 12 kW residential electric range when calculating the
service-entrance conductors?
A. 9.6 kW
B. 12 kW
C. 8 kW
D. 5.4 kW
Answer: C
Conceptual Explanation: Based on Table 220.55, Column C, one range not over 12 kW is
calculated at 8 kW.
, 4. Which of the following is required for a 125-volt, single-phase, 15- or 20-ampere receptacle
installed in a residential crawl space at or below grade level?
A. AFCI protection only
B. GFCI protection only
C. Both AFCI and GFCI protection
D. No special protection required if not readily accessible
Answer: B
Conceptual Explanation: NEC 210.8(A)(4) requires GFCI protection for all 125-volt,
single-phase, 15- and 20-ampere receptacles installed in crawl spaces at or below grade
level.
5. What is the minimum volume allowance required for each 12 AWG conductor when
calculating box fill according to NEC Table 314.16(B)?
A. 2.25 cubic inches
B. 2.00 cubic inches
C. 2.50 cubic inches
D. 3.00 cubic inches
Answer: A
Conceptual Explanation: Table 314.16(B) specifies that a 12 AWG conductor requires
2.25 cubic inches of space within an outlet box.
SINGLE-FAMILY DWELLING
ELECTRICAL CONTRACTOR EXAM
QUESTIONS AND CORRECT ANSWERS
WITH EXPLANATIONS
1. A 200-ampere single-phase residential service is being installed using 2/0 AWG copper
ungrounded conductors. What is the minimum size required for the copper grounding
electrode conductor to a concrete-encased electrode?
A. 6 AWG
B. 4 AWG
C. 2 AWG
D. 1/0 AWG
Answer: A
Conceptual Explanation: According to NEC 250.66(B), if the grounding electrode
conductor is connected to a concrete-encased electrode, that portion of the conductor that
is the sole connection to the grounding electrode shall not be required to be larger than 4
AWG copper; however, many residential codes specify 4 or 6, and specifically for concrete-
encased, 6 AWG is the max required for the electrode itself.
,2. In a residential kitchen, what is the maximum distance allowed between receptacles along
the wall line of a countertop space?
A. 2 feet
B. 4 feet
C. 6 feet
D. 12 feet
Answer: B
Conceptual Explanation: NEC 210.52(C)(1) states that receptacles shall be installed so
that no point along the wall line is more than 24 inches (2 feet) measured horizontally from
a receptacle outlet. This effectively means a maximum of 4 feet between receptacles.
3. What is the demand load for one 12 kW residential electric range when calculating the
service-entrance conductors?
A. 9.6 kW
B. 12 kW
C. 8 kW
D. 5.4 kW
Answer: C
Conceptual Explanation: Based on Table 220.55, Column C, one range not over 12 kW is
calculated at 8 kW.
, 4. Which of the following is required for a 125-volt, single-phase, 15- or 20-ampere receptacle
installed in a residential crawl space at or below grade level?
A. AFCI protection only
B. GFCI protection only
C. Both AFCI and GFCI protection
D. No special protection required if not readily accessible
Answer: B
Conceptual Explanation: NEC 210.8(A)(4) requires GFCI protection for all 125-volt,
single-phase, 15- and 20-ampere receptacles installed in crawl spaces at or below grade
level.
5. What is the minimum volume allowance required for each 12 AWG conductor when
calculating box fill according to NEC Table 314.16(B)?
A. 2.25 cubic inches
B. 2.00 cubic inches
C. 2.50 cubic inches
D. 3.00 cubic inches
Answer: A
Conceptual Explanation: Table 314.16(B) specifies that a 12 AWG conductor requires
2.25 cubic inches of space within an outlet box.
