ARIZONA CR-11 ELECTRICAL
CONTRACTOR EXAM – QUESTIONS AND
ANSWERS | VERIFIED AND WELL
DETAILED ANSWERS | PLUS RATIONALES
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SECTION 1: GROUNDING & BONDING
Question 1:
What is the primary purpose of grounding in an electrical system?
A) To prevent electrical overloads
B) To provide a safe path for fault current to earth
C) To increase circuit voltage
D) To reduce conductor insulation
Answer: B
Rationale: Grounding provides a controlled path for fault current to return to earth,
reducing the risk of shock or equipment damage. It is a fundamental safety requirement
in all electrical systems .
Question 2:
What is the purpose of a grounding electrode conductor?
A) To support conductors
B) To insulate wires
,C) To connect the electrical system to a grounding electrode
D) To enhance signal transmission
Answer: C
Rationale: Grounding electrode conductors bond electrical systems to earth electrodes.
This connection provides a path for fault current and lightning to dissipate safely into
the earth .
Question 3:
What is the minimum size copper equipment grounding conductor required for a
200-ampere feeder circuit protected by a 200-ampere overcurrent device?
A) 8 AWG
B) 6 AWG
C) 4 AWG
D) 3 AWG
Answer: B
Rationale: Per NEC Table 250.122, a 200-ampere overcurrent device requires a 6 AWG
copper equipment grounding conductor .
Question 4:
What is the primary purpose of a bonding jumper in a separately derived system?
A) To provide a low-impedance path for fault current
B) To increase the voltage of the system
C) To reduce the resistance of the grounding electrode
D) To connect the system to the utility transformer
,Answer: A
Rationale: The bonding jumper ensures a low-impedance path for fault current to
operate the overcurrent protection device, clearing the fault quickly .
Question 5:
A 277/480V, 3-phase, 4-wire service supplies a commercial building with nonlinear
loads. The neutral conductor is required to be counted as a current-carrying
conductor for ampacity adjustment. What is the minimum size neutral conductor
required if the phase conductors are 500 kcmil copper, and the neutral is not
oversized to handle harmonics?
A) 1/0 AWG copper
B) 2/0 AWG copper
C) 3/0 AWG copper
D) 4/0 AWG copper
Answer: C
Rationale: For 277/480V systems with nonlinear loads, the neutral carries harmonic
currents and is considered a current-carrying conductor. Per NEC 250.30(A)(1) and Table
250.102(C)(1), the minimum size grounded conductor is based on the phase conductor
area. For 500 kcmil copper phase conductors, the required neutral is 3/0 AWG copper .
Question 6:
A 400 A, 208Y/120V, 3-phase, 4-wire service has parallel 3/0 AWG copper per
phase. What is the minimum size copper equipment grounding conductor (EGC)
per NEC 250.122?
A) 1/0 AWG
, B) 2 AWG
C) 4 AWG
D) 6 AWG
Answer: C
Rationale: Per NEC 250.122, the EGC is sized based on the overcurrent device rating. For
a 400 A overcurrent device, Table 250.122 requires a 4 AWG copper EGC .
SECTION 2: SERVICE & FEEDER SIZING
Question 7:
What is the minimum size of a grounded conductor (neutral) required for a 200-
ampere residential service if the service-entrance conductors are 2/0 AWG copper?
A) 2 AWG copper
B) 3 AWG copper
C) 4 AWG copper
D) 1/0 AWG copper
Answer: C
Rationale: According to NEC Table 250.102(C)(1), the minimum neutral conductor must
be sized at least 12.5% of the total circular mil area of the largest ungrounded service
conductor. For a 200 A service with 2/0 AWG copper, a 4 AWG copper neutral is
required .
Question 8:
A feeder supplies a panelboard with 120/208V, single-phase loads. The calculated
load is 180 A continuous and 120 A noncontinuous. Using 75°C terminals, what is
CONTRACTOR EXAM – QUESTIONS AND
ANSWERS | VERIFIED AND WELL
DETAILED ANSWERS | PLUS RATIONALES
| GUARANTEED PASS | LATEST EXAM
UPDATE
SECTION 1: GROUNDING & BONDING
Question 1:
What is the primary purpose of grounding in an electrical system?
A) To prevent electrical overloads
B) To provide a safe path for fault current to earth
C) To increase circuit voltage
D) To reduce conductor insulation
Answer: B
Rationale: Grounding provides a controlled path for fault current to return to earth,
reducing the risk of shock or equipment damage. It is a fundamental safety requirement
in all electrical systems .
Question 2:
What is the purpose of a grounding electrode conductor?
A) To support conductors
B) To insulate wires
,C) To connect the electrical system to a grounding electrode
D) To enhance signal transmission
Answer: C
Rationale: Grounding electrode conductors bond electrical systems to earth electrodes.
This connection provides a path for fault current and lightning to dissipate safely into
the earth .
Question 3:
What is the minimum size copper equipment grounding conductor required for a
200-ampere feeder circuit protected by a 200-ampere overcurrent device?
A) 8 AWG
B) 6 AWG
C) 4 AWG
D) 3 AWG
Answer: B
Rationale: Per NEC Table 250.122, a 200-ampere overcurrent device requires a 6 AWG
copper equipment grounding conductor .
Question 4:
What is the primary purpose of a bonding jumper in a separately derived system?
A) To provide a low-impedance path for fault current
B) To increase the voltage of the system
C) To reduce the resistance of the grounding electrode
D) To connect the system to the utility transformer
,Answer: A
Rationale: The bonding jumper ensures a low-impedance path for fault current to
operate the overcurrent protection device, clearing the fault quickly .
Question 5:
A 277/480V, 3-phase, 4-wire service supplies a commercial building with nonlinear
loads. The neutral conductor is required to be counted as a current-carrying
conductor for ampacity adjustment. What is the minimum size neutral conductor
required if the phase conductors are 500 kcmil copper, and the neutral is not
oversized to handle harmonics?
A) 1/0 AWG copper
B) 2/0 AWG copper
C) 3/0 AWG copper
D) 4/0 AWG copper
Answer: C
Rationale: For 277/480V systems with nonlinear loads, the neutral carries harmonic
currents and is considered a current-carrying conductor. Per NEC 250.30(A)(1) and Table
250.102(C)(1), the minimum size grounded conductor is based on the phase conductor
area. For 500 kcmil copper phase conductors, the required neutral is 3/0 AWG copper .
Question 6:
A 400 A, 208Y/120V, 3-phase, 4-wire service has parallel 3/0 AWG copper per
phase. What is the minimum size copper equipment grounding conductor (EGC)
per NEC 250.122?
A) 1/0 AWG
, B) 2 AWG
C) 4 AWG
D) 6 AWG
Answer: C
Rationale: Per NEC 250.122, the EGC is sized based on the overcurrent device rating. For
a 400 A overcurrent device, Table 250.122 requires a 4 AWG copper EGC .
SECTION 2: SERVICE & FEEDER SIZING
Question 7:
What is the minimum size of a grounded conductor (neutral) required for a 200-
ampere residential service if the service-entrance conductors are 2/0 AWG copper?
A) 2 AWG copper
B) 3 AWG copper
C) 4 AWG copper
D) 1/0 AWG copper
Answer: C
Rationale: According to NEC Table 250.102(C)(1), the minimum neutral conductor must
be sized at least 12.5% of the total circular mil area of the largest ungrounded service
conductor. For a 200 A service with 2/0 AWG copper, a 4 AWG copper neutral is
required .
Question 8:
A feeder supplies a panelboard with 120/208V, single-phase loads. The calculated
load is 180 A continuous and 120 A noncontinuous. Using 75°C terminals, what is
