New York City DCAS Electrician Civil
Service Exam Questions And Well Graded
Solutions With Rationales Updated
Section 1: NEC Code Compliance (Questions 1-15)
Q1. A junction box contains four 12 AWG THHN copper current-carrying conductors and one 12
AWG grounding conductor. The box is to be installed in a dry location. What is the minimum
cubic inch capacity required for this box per NEC 314.16?
A) 12.0 cu in
B) 15.0 cu in
C) 18.0 cu in
D) 20.25 cu in
Correct Answer: B) 15.0 cu in
Rationale: NEC 314.16(B)(1) requires each 12 AWG conductor to be counted as 2.25 cu in. Four
current-carrying conductors = 4 × 2.25 = 9.0 cu in. The grounding conductor (one) is counted as
1 volume allowance (2.25 cu in). Total allowances = 5 × 2.25 = 11.25 cu in. While 11.25 is the
mathematical minimum, a standard 4" x 4" x 1.5" box is 21.0 cu in, but a 4" x 4" x 1.25" box is
12.5 cu in, which is insufficient. Many standard boxes in this range are 15.0 cu in, making B the
most practical answer. Some interpretations may include an additional allowance for internal
clamps, pushing the minimum to 13.5 or 15.75, making 15.0 the closest standard size .
Q2. According to NEC Article 110.26, what is the MINIMUM required working space depth in
front of electrical equipment operating at 480V phase-to-phase with exposed live parts on one
side and grounded parts on the other side?
A. 3 feet
B. 3.5 feet
C. 4 feet
D. 5 feet
Correct Answer: A. 3 feet
Rationale: NEC Table 110.26(A)(1) specifies minimum working space depths based on voltage
and conditions. For 480V (nominal, phase-to-phase) with Condition 1 (exposed live parts on one
side, grounded on other), the minimum depth is 3 feet. Condition 2 (live parts both sides)
requires 3.5 feet; Condition 3 (live parts both sides, accessible from either side) requires 4 feet .
,Q3. A 120V branch circuit supplies a continuous load of 16A. What is the MINIMUM ampere
rating for the overcurrent protective device per NEC requirements?
A. 16A
B. 20A
C. 25A
D. 30A
Correct Answer: B. 20A
Rationale: NEC 210.20(A) requires overcurrent devices for continuous loads (operating 3+
hours) to be rated at least 125% of the continuous load. 16A × 1.25 = 20A. Standard breaker
sizes per NEC 240.6 include 15A, 20A, 25A, 30A. A 20A breaker is the minimum standard size
meeting the 125% requirement .
Q4. What is the MAXIMUM number of 90-degree bends allowed in a single conduit run
between pull points per NEC Article 358.26?
A. 2
B. 3
C. 4
D. 5
Correct Answer: C. 4
Rationale: NEC 358.26 (EMT), 344.26 (RMC), and 352.26 (PVC) all limit conduit bends to a
maximum of 360 degrees total (four 90-degree bends) between pull points (boxes, condulets,
etc.) to prevent conductor damage during pulling. Exceeding this requires an additional pull
point .
Q5. According to NEC Article 210.8(A), GFCI protection is REQUIRED for which of the following
125V, 15A or 20A receptacles in a dwelling unit?
A. Living room receptacles
B. Bedroom receptacles
C. Garage receptacles
D. Dining room receptacles
Correct Answer: C. Garage receptacles
Rationale: NEC 210.8(A) requires GFCI protection for 125V, 15A/20A receptacles in specific
dwelling unit locations: bathrooms, garages, outdoors, crawl spaces, basements, kitchens, sinks,
laundry areas, and boathouses. Living room, bedroom, and dining room receptacles do not
require GFCI protection unless within 6 feet of a sink .
,Q6. A 20A, 120V branch circuit supplies receptacles in a dwelling unit bedroom. What is the
MAXIMUM spacing between receptacles along the wall line per NEC Article 210.52(A)?
A. 6 feet
B. 10 feet
C. 12 feet
D. 15 feet
Correct Answer: C. 12 feet
Rationale: NEC 210.52(A)(1) states that receptacles shall be installed so that no point measured
horizontally along the floor line in any wall space is more than 6 feet from a receptacle outlet.
This means the maximum spacing between two receptacles is 12 feet, as each receptacle covers
6 feet in each direction .
Q7. What is the MINIMUM size copper equipment grounding conductor required for a 60-
ampere overcurrent device protecting a branch circuit?
A. 14 AWG
B. 12 AWG
C. 10 AWG
D. 8 AWG
Correct Answer: C. 10 AWG
Rationale: NEC Table 250.122 specifies equipment grounding conductor sizing based on the
rating of the overcurrent protective device. For a 60A breaker, the minimum copper EGC size is
10 AWG .
Q8. According to the NEC, the maximum number of current-carrying conductors allowed in a
conduit before derating is required is:
A. 2
B. 3
C. 4
D. 6
Correct Answer: B. 3
Rationale: Derating begins when more than 3 current-carrying conductors are present in a
raceway or cable. This is found in NEC 310.15(C)(1) .
Q9. What is the maximum allowable voltage drop for a branch circuit (NEC recommendation)?
A. 1%
B. 3%
, C. 5%
D. 10%
Correct Answer: B. 3%
Rationale: NEC recommends 3% for branch circuits and 5% total for feeder + branch circuit
(Informational Note) .
Q10. In a dwelling, AFCI protection is required for:
A. Bathroom receptacles
B. Bedroom, living room, and similar areas
C. Garage door openers
D. Outdoor lighting
Correct Answer: B. Bedroom, living room, and similar areas
Rationale: NEC 210.12 requires AFCI protection for all 120V, 15A and 20A branch circuits
supplying outlets in dwelling unit kitchens, family rooms, dining rooms, living rooms, parlors,
libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas, and
similar rooms .
Q11. The grounded conductor of a 120/240-volt single-phase residential service must be
identified by which color?
A. Green
B. Bare copper
C. White or natural gray
D. Yellow
Correct Answer: C. White or natural gray
Rationale: NEC 200.6(A) requires grounded (neutral) conductors 6 AWG and smaller to have
white or gray insulation or three continuous white/gray stripes. Green or bare is reserved for
equipment grounding conductors .
Q12. A continuous load of 40 amperes on a branch circuit requires an overcurrent device rated
at least:
A. 40 A
B. 45 A
C. 50 A
D. 60 A
Correct Answer: C. 50 A
Service Exam Questions And Well Graded
Solutions With Rationales Updated
Section 1: NEC Code Compliance (Questions 1-15)
Q1. A junction box contains four 12 AWG THHN copper current-carrying conductors and one 12
AWG grounding conductor. The box is to be installed in a dry location. What is the minimum
cubic inch capacity required for this box per NEC 314.16?
A) 12.0 cu in
B) 15.0 cu in
C) 18.0 cu in
D) 20.25 cu in
Correct Answer: B) 15.0 cu in
Rationale: NEC 314.16(B)(1) requires each 12 AWG conductor to be counted as 2.25 cu in. Four
current-carrying conductors = 4 × 2.25 = 9.0 cu in. The grounding conductor (one) is counted as
1 volume allowance (2.25 cu in). Total allowances = 5 × 2.25 = 11.25 cu in. While 11.25 is the
mathematical minimum, a standard 4" x 4" x 1.5" box is 21.0 cu in, but a 4" x 4" x 1.25" box is
12.5 cu in, which is insufficient. Many standard boxes in this range are 15.0 cu in, making B the
most practical answer. Some interpretations may include an additional allowance for internal
clamps, pushing the minimum to 13.5 or 15.75, making 15.0 the closest standard size .
Q2. According to NEC Article 110.26, what is the MINIMUM required working space depth in
front of electrical equipment operating at 480V phase-to-phase with exposed live parts on one
side and grounded parts on the other side?
A. 3 feet
B. 3.5 feet
C. 4 feet
D. 5 feet
Correct Answer: A. 3 feet
Rationale: NEC Table 110.26(A)(1) specifies minimum working space depths based on voltage
and conditions. For 480V (nominal, phase-to-phase) with Condition 1 (exposed live parts on one
side, grounded on other), the minimum depth is 3 feet. Condition 2 (live parts both sides)
requires 3.5 feet; Condition 3 (live parts both sides, accessible from either side) requires 4 feet .
,Q3. A 120V branch circuit supplies a continuous load of 16A. What is the MINIMUM ampere
rating for the overcurrent protective device per NEC requirements?
A. 16A
B. 20A
C. 25A
D. 30A
Correct Answer: B. 20A
Rationale: NEC 210.20(A) requires overcurrent devices for continuous loads (operating 3+
hours) to be rated at least 125% of the continuous load. 16A × 1.25 = 20A. Standard breaker
sizes per NEC 240.6 include 15A, 20A, 25A, 30A. A 20A breaker is the minimum standard size
meeting the 125% requirement .
Q4. What is the MAXIMUM number of 90-degree bends allowed in a single conduit run
between pull points per NEC Article 358.26?
A. 2
B. 3
C. 4
D. 5
Correct Answer: C. 4
Rationale: NEC 358.26 (EMT), 344.26 (RMC), and 352.26 (PVC) all limit conduit bends to a
maximum of 360 degrees total (four 90-degree bends) between pull points (boxes, condulets,
etc.) to prevent conductor damage during pulling. Exceeding this requires an additional pull
point .
Q5. According to NEC Article 210.8(A), GFCI protection is REQUIRED for which of the following
125V, 15A or 20A receptacles in a dwelling unit?
A. Living room receptacles
B. Bedroom receptacles
C. Garage receptacles
D. Dining room receptacles
Correct Answer: C. Garage receptacles
Rationale: NEC 210.8(A) requires GFCI protection for 125V, 15A/20A receptacles in specific
dwelling unit locations: bathrooms, garages, outdoors, crawl spaces, basements, kitchens, sinks,
laundry areas, and boathouses. Living room, bedroom, and dining room receptacles do not
require GFCI protection unless within 6 feet of a sink .
,Q6. A 20A, 120V branch circuit supplies receptacles in a dwelling unit bedroom. What is the
MAXIMUM spacing between receptacles along the wall line per NEC Article 210.52(A)?
A. 6 feet
B. 10 feet
C. 12 feet
D. 15 feet
Correct Answer: C. 12 feet
Rationale: NEC 210.52(A)(1) states that receptacles shall be installed so that no point measured
horizontally along the floor line in any wall space is more than 6 feet from a receptacle outlet.
This means the maximum spacing between two receptacles is 12 feet, as each receptacle covers
6 feet in each direction .
Q7. What is the MINIMUM size copper equipment grounding conductor required for a 60-
ampere overcurrent device protecting a branch circuit?
A. 14 AWG
B. 12 AWG
C. 10 AWG
D. 8 AWG
Correct Answer: C. 10 AWG
Rationale: NEC Table 250.122 specifies equipment grounding conductor sizing based on the
rating of the overcurrent protective device. For a 60A breaker, the minimum copper EGC size is
10 AWG .
Q8. According to the NEC, the maximum number of current-carrying conductors allowed in a
conduit before derating is required is:
A. 2
B. 3
C. 4
D. 6
Correct Answer: B. 3
Rationale: Derating begins when more than 3 current-carrying conductors are present in a
raceway or cable. This is found in NEC 310.15(C)(1) .
Q9. What is the maximum allowable voltage drop for a branch circuit (NEC recommendation)?
A. 1%
B. 3%
, C. 5%
D. 10%
Correct Answer: B. 3%
Rationale: NEC recommends 3% for branch circuits and 5% total for feeder + branch circuit
(Informational Note) .
Q10. In a dwelling, AFCI protection is required for:
A. Bathroom receptacles
B. Bedroom, living room, and similar areas
C. Garage door openers
D. Outdoor lighting
Correct Answer: B. Bedroom, living room, and similar areas
Rationale: NEC 210.12 requires AFCI protection for all 120V, 15A and 20A branch circuits
supplying outlets in dwelling unit kitchens, family rooms, dining rooms, living rooms, parlors,
libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas, and
similar rooms .
Q11. The grounded conductor of a 120/240-volt single-phase residential service must be
identified by which color?
A. Green
B. Bare copper
C. White or natural gray
D. Yellow
Correct Answer: C. White or natural gray
Rationale: NEC 200.6(A) requires grounded (neutral) conductors 6 AWG and smaller to have
white or gray insulation or three continuous white/gray stripes. Green or bare is reserved for
equipment grounding conductors .
Q12. A continuous load of 40 amperes on a branch circuit requires an overcurrent device rated
at least:
A. 40 A
B. 45 A
C. 50 A
D. 60 A
Correct Answer: C. 50 A
