NYC DCAS Electrician Exam Questions with
Correct Answers (Verified Answers) Plus
Rationales 100% Correct
Question 1
The frames of all portable motors over a certain voltage must be guarded or
grounded. What is the voltage?
A) 100 volts
B) 120 volts
C) 150 volts
D) 220 volts
Correct Answer
C) 150 volts
Article 430.243
Question 2
The value of current, time, or both at which an adjustable circuit breaker is set to trip
is known as?
A) Inverse time
B) Ampacity
C) Automatic
D) Setting
Correct Answer
D) Setting.
Art. 100 Defintions
Page 1 of 86
,Question 3
An insulated grounded conductor shall have insulation that is?
A) service rated
B) green
C) suitable for use as an ungrounded conductor
D) listed for underground use
Correct Answer
C) suitable for use as an ungrounded conductor
Article 200.2 (A)
Page 2 of 86
,Question 4
The working clearance between live parts for a system operating at 480 volts with
exposed live parts on one side and grounded parts on the other side is?
A) 1 ft
B) 2 ft
C) 3 ft 6in
D) 4 ft
Correct Answer
C) 3 ft 6 in
Article 110.26 (A)
Question 1: According to the National Electrical Code (NEC) and standard
practice for NYC electrical installations, what is the maximum continuous load
permitted on a 20-ampere branch circuit?
A. 16 amperes
B. 20 amperes
C. 15 amperes
D. 12 amperes
CORRECT ANSWER: A. 16 amperes
Rationale: NEC 210.19(A) and 210.20(A) require that continuous loads (operating for
three hours or more) shall not exceed 80 percent of the branch-circuit rating. For a
20-ampere circuit, 80 percent of 20 A equals 16 A. This derating prevents
overheating of conductors and overcurrent devices under sustained load conditions
common in commercial and residential NYC installations.
Question 2: What is the primary purpose of equipment grounding in an
electrical system?
A. To provide a path for lightning protection only
B. To carry fault current and facilitate operation of overcurrent devices
C. To reduce voltage drop on the grounded conductor
D. To serve as the neutral return path under normal conditions
CORRECT ANSWER: B. To carry fault current and facilitate operation of
overcurrent devices
Rationale: Equipment grounding conductors (EGCs) provide a low-impedance path
for ground-fault current, enabling circuit breakers or fuses to clear the fault quickly.
This is a fundamental safety requirement under NEC Article 250 and is critical for
protecting personnel from shock hazards in NYC buildings.
Page 3 of 86
, Question 3: In a three-phase, four-wire wye system, the line-to-neutral voltage
is 120 V. What is the approximate line-to-line voltage?
A. 120 V
B. 208 V
C. 240 V
D. 277 V
CORRECT ANSWER: B. 208 V
Rationale: In a balanced three-phase wye system, the line-to-line voltage equals the
line-to-neutral voltage multiplied by √3 (approximately 1.732). Therefore, 120 V ×
1.732 ≈ 208 V. This configuration is extremely common in NYC commercial
buildings for both lighting and power loads.
Question 4: Which of the following best describes the function of a GFCI
device?
A. It protects against overloads by thermal action
B. It detects current imbalance between hot and neutral and opens the circuit
C. It limits voltage spikes caused by lightning
D. It provides isolation between primary and secondary of a transformer
CORRECT ANSWER: B. It detects current imbalance between hot and neutral
and opens the circuit
Rationale: A Ground-Fault Circuit Interrupter continuously monitors the current
leaving on the ungrounded conductor and returning on the grounded conductor.
Any difference greater than approximately 5 mA indicates leakage to ground, and
the device trips. This is required in wet or damp locations per NEC 210.8 and is
heavily enforced in NYC inspections.
Question 5: What is the minimum burial depth for a direct-buried 120/240 V
residential branch-circuit cable under a driveway according to NEC Table
300.5?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
CORRECT ANSWER: D. 24 inches
Rationale: NEC Table 300.5 Column 4 requires a minimum cover of 24 inches for
residential branch circuits rated 120 V or less with GFCI protection and maximum
overcurrent protection of 20 A when installed under driveways or parking areas
Page 4 of 86
Correct Answers (Verified Answers) Plus
Rationales 100% Correct
Question 1
The frames of all portable motors over a certain voltage must be guarded or
grounded. What is the voltage?
A) 100 volts
B) 120 volts
C) 150 volts
D) 220 volts
Correct Answer
C) 150 volts
Article 430.243
Question 2
The value of current, time, or both at which an adjustable circuit breaker is set to trip
is known as?
A) Inverse time
B) Ampacity
C) Automatic
D) Setting
Correct Answer
D) Setting.
Art. 100 Defintions
Page 1 of 86
,Question 3
An insulated grounded conductor shall have insulation that is?
A) service rated
B) green
C) suitable for use as an ungrounded conductor
D) listed for underground use
Correct Answer
C) suitable for use as an ungrounded conductor
Article 200.2 (A)
Page 2 of 86
,Question 4
The working clearance between live parts for a system operating at 480 volts with
exposed live parts on one side and grounded parts on the other side is?
A) 1 ft
B) 2 ft
C) 3 ft 6in
D) 4 ft
Correct Answer
C) 3 ft 6 in
Article 110.26 (A)
Question 1: According to the National Electrical Code (NEC) and standard
practice for NYC electrical installations, what is the maximum continuous load
permitted on a 20-ampere branch circuit?
A. 16 amperes
B. 20 amperes
C. 15 amperes
D. 12 amperes
CORRECT ANSWER: A. 16 amperes
Rationale: NEC 210.19(A) and 210.20(A) require that continuous loads (operating for
three hours or more) shall not exceed 80 percent of the branch-circuit rating. For a
20-ampere circuit, 80 percent of 20 A equals 16 A. This derating prevents
overheating of conductors and overcurrent devices under sustained load conditions
common in commercial and residential NYC installations.
Question 2: What is the primary purpose of equipment grounding in an
electrical system?
A. To provide a path for lightning protection only
B. To carry fault current and facilitate operation of overcurrent devices
C. To reduce voltage drop on the grounded conductor
D. To serve as the neutral return path under normal conditions
CORRECT ANSWER: B. To carry fault current and facilitate operation of
overcurrent devices
Rationale: Equipment grounding conductors (EGCs) provide a low-impedance path
for ground-fault current, enabling circuit breakers or fuses to clear the fault quickly.
This is a fundamental safety requirement under NEC Article 250 and is critical for
protecting personnel from shock hazards in NYC buildings.
Page 3 of 86
, Question 3: In a three-phase, four-wire wye system, the line-to-neutral voltage
is 120 V. What is the approximate line-to-line voltage?
A. 120 V
B. 208 V
C. 240 V
D. 277 V
CORRECT ANSWER: B. 208 V
Rationale: In a balanced three-phase wye system, the line-to-line voltage equals the
line-to-neutral voltage multiplied by √3 (approximately 1.732). Therefore, 120 V ×
1.732 ≈ 208 V. This configuration is extremely common in NYC commercial
buildings for both lighting and power loads.
Question 4: Which of the following best describes the function of a GFCI
device?
A. It protects against overloads by thermal action
B. It detects current imbalance between hot and neutral and opens the circuit
C. It limits voltage spikes caused by lightning
D. It provides isolation between primary and secondary of a transformer
CORRECT ANSWER: B. It detects current imbalance between hot and neutral
and opens the circuit
Rationale: A Ground-Fault Circuit Interrupter continuously monitors the current
leaving on the ungrounded conductor and returning on the grounded conductor.
Any difference greater than approximately 5 mA indicates leakage to ground, and
the device trips. This is required in wet or damp locations per NEC 210.8 and is
heavily enforced in NYC inspections.
Question 5: What is the minimum burial depth for a direct-buried 120/240 V
residential branch-circuit cable under a driveway according to NEC Table
300.5?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
CORRECT ANSWER: D. 24 inches
Rationale: NEC Table 300.5 Column 4 requires a minimum cover of 24 inches for
residential branch circuits rated 120 V or less with GFCI protection and maximum
overcurrent protection of 20 A when installed under driveways or parking areas
Page 4 of 86
