Arizona CR-11 Electrical Contractor
Exam: 300 Practice Questions &
Answers Rationales [Graded A+]
Section 1: General Electrical Knowledge & Theory
1. What is the primary purpose of a circuit breaker?
• A. Increase voltage
• B. Protect circuits from overloads and short circuits ✓
• C. Store electrical energy
• D. Convert AC to DC
Rationale: Circuit breakers are safety devices designed to
automatically interrupt current flow when an overload or short
circuit occurs, preventing damage, fire, and hazards .
2. Ohm's Law is expressed as:
• A. P = IV
• B. V = IR ✓
• C. I = PR
• D. R = VI²
Rationale: Ohm's Law defines the relationship between voltage,
current, and resistance, forming the basis of electrical
calculations in circuit design and troubleshooting .
3. The unit of electrical resistance is:
• A. Volt
, • B. Ampere
• C. Ohm ✓
• D. Watt
Rationale: Resistance is measured in ohms (Ω), which indicates
how much a material opposes the flow of electrical current .
4. A grounded conductor is commonly known as:
• A. Hot wire
• B. Neutral wire ✓
• C. Load wire
• D. Bond wire
Rationale: The neutral (grounded conductor) carries current
back to the source and is typically connected to earth ground at
the service entrance .
5. What does GFCI stand for?
• A. Ground Fault Circuit Indicator
• B. Ground Fault Circuit Interrupter ✓
• C. General Flow Current Insulator
• D. Ground Feed Circuit Interface
Rationale: A GFCI protects people from electric shock by
shutting off power when it detects leakage current to ground .
6. The standard voltage for residential service in the U.S. is
typically:
• A. 120V only
• B. 120/240V single phase ✓
• C. 240/480V three phase
• D. 277/480V single phase
,Rationale: Most residential services in Arizona use a 120/240-
volt single-phase system with two ungrounded conductors and
a grounded neutral .
7. According to the NEC, the primary purpose of
overcurrent protection devices is to:
• A. Increase the voltage supplied to equipment
• B. Reduce electrical resistance in conductors
• C. Protect conductors and equipment from excessive
current ✓
• D. Improve power factor in circuits
Rationale: Overcurrent protection devices such as fuses and
circuit breakers are designed to open the circuit when current
exceeds safe levels, preventing conductor overheating,
insulation damage, and potential fires .
8. The main purpose of bonding electrical equipment is to:
• A. Increase circuit voltage
• B. Provide an effective path for fault current ✓
• C. Reduce conductor size
• D. Eliminate grounding requirements
Rationale: Bonding connects conductive parts together to
provide a low-impedance path for fault current, allowing
protective devices to operate .
Section 2: Wiring Methods & Conductors
9. What is the minimum copper conductor size commonly
used for a 20-amp branch circuit according to NEC
requirements?
• A. 18 AWG
, • B. 16 AWG
• C. 12 AWG ✓
• D. 10 AWG
Rationale: NEC generally requires 12 AWG copper conductors
for 20-amp branch circuits unless special conditions permit
otherwise .
10. What type of wiring method is commonly used for
exposed commercial applications?
• A. Plastic furniture tubing
• B. Electrical metallic tubing (EMT) ✓
• C. Garden hose
• D. Wooden conduit
Rationale: EMT is a common raceway system used in
commercial installations because it provides mechanical
protection and allows conductor replacement .
11. The maximum number of conductors permitted in a 1-
in. PVC conduit without exceeding the 40% fill limit for
three #2 AWG copper THHN conductors is:
• A. 3 ✓
• B. 4
• C. 5
• D. 6
Rationale: Annex C shows that only three #2 AWG conductors
fit within 40% of a 1-in. PVC conduit .
12. The NEC permits the use of "flexible metal conduit"
(FMC) for branch-circuit wiring in which of the following
environments?
Exam: 300 Practice Questions &
Answers Rationales [Graded A+]
Section 1: General Electrical Knowledge & Theory
1. What is the primary purpose of a circuit breaker?
• A. Increase voltage
• B. Protect circuits from overloads and short circuits ✓
• C. Store electrical energy
• D. Convert AC to DC
Rationale: Circuit breakers are safety devices designed to
automatically interrupt current flow when an overload or short
circuit occurs, preventing damage, fire, and hazards .
2. Ohm's Law is expressed as:
• A. P = IV
• B. V = IR ✓
• C. I = PR
• D. R = VI²
Rationale: Ohm's Law defines the relationship between voltage,
current, and resistance, forming the basis of electrical
calculations in circuit design and troubleshooting .
3. The unit of electrical resistance is:
• A. Volt
, • B. Ampere
• C. Ohm ✓
• D. Watt
Rationale: Resistance is measured in ohms (Ω), which indicates
how much a material opposes the flow of electrical current .
4. A grounded conductor is commonly known as:
• A. Hot wire
• B. Neutral wire ✓
• C. Load wire
• D. Bond wire
Rationale: The neutral (grounded conductor) carries current
back to the source and is typically connected to earth ground at
the service entrance .
5. What does GFCI stand for?
• A. Ground Fault Circuit Indicator
• B. Ground Fault Circuit Interrupter ✓
• C. General Flow Current Insulator
• D. Ground Feed Circuit Interface
Rationale: A GFCI protects people from electric shock by
shutting off power when it detects leakage current to ground .
6. The standard voltage for residential service in the U.S. is
typically:
• A. 120V only
• B. 120/240V single phase ✓
• C. 240/480V three phase
• D. 277/480V single phase
,Rationale: Most residential services in Arizona use a 120/240-
volt single-phase system with two ungrounded conductors and
a grounded neutral .
7. According to the NEC, the primary purpose of
overcurrent protection devices is to:
• A. Increase the voltage supplied to equipment
• B. Reduce electrical resistance in conductors
• C. Protect conductors and equipment from excessive
current ✓
• D. Improve power factor in circuits
Rationale: Overcurrent protection devices such as fuses and
circuit breakers are designed to open the circuit when current
exceeds safe levels, preventing conductor overheating,
insulation damage, and potential fires .
8. The main purpose of bonding electrical equipment is to:
• A. Increase circuit voltage
• B. Provide an effective path for fault current ✓
• C. Reduce conductor size
• D. Eliminate grounding requirements
Rationale: Bonding connects conductive parts together to
provide a low-impedance path for fault current, allowing
protective devices to operate .
Section 2: Wiring Methods & Conductors
9. What is the minimum copper conductor size commonly
used for a 20-amp branch circuit according to NEC
requirements?
• A. 18 AWG
, • B. 16 AWG
• C. 12 AWG ✓
• D. 10 AWG
Rationale: NEC generally requires 12 AWG copper conductors
for 20-amp branch circuits unless special conditions permit
otherwise .
10. What type of wiring method is commonly used for
exposed commercial applications?
• A. Plastic furniture tubing
• B. Electrical metallic tubing (EMT) ✓
• C. Garden hose
• D. Wooden conduit
Rationale: EMT is a common raceway system used in
commercial installations because it provides mechanical
protection and allows conductor replacement .
11. The maximum number of conductors permitted in a 1-
in. PVC conduit without exceeding the 40% fill limit for
three #2 AWG copper THHN conductors is:
• A. 3 ✓
• B. 4
• C. 5
• D. 6
Rationale: Annex C shows that only three #2 AWG conductors
fit within 40% of a 1-in. PVC conduit .
12. The NEC permits the use of "flexible metal conduit"
(FMC) for branch-circuit wiring in which of the following
environments?
