AZ C-11 Electrical Contractor Exam
Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary purpose of a circuit breaker in an electrical
system?
A. Increase voltage
B. Store energy
C. Protect circuits from overcurrent
D. Measure current
Rationale: Circuit breakers are designed to interrupt current flow in
the event of overloads or short circuits, preventing damage to wiring
and equipment.
2. Which type of wiring is most commonly used for residential interior
wiring?
A. Aluminum conduit
B. Non-metallic sheathed cable (NM)
C. Rigid metal conduit (RMC)
D. Flexible metal conduit
Rationale: NM cable, often called Romex, is widely used in residential
wiring due to its ease of installation and suitability for dry locations.
3. The National Electrical Code (NEC) requires that all 15- and 20-
ampere, 120-volt branch circuits have what type of grounding?
A. Optional
B. Metallic conduit only
C. Equipment grounding conductor
D. Grounding is not required
Rationale: NEC mandates an equipment grounding conductor for
safety to prevent electrical shock and ensure proper operation of
overcurrent protection devices.
,4. Which device is used to detect and protect against ground faults?
A. Circuit breaker
B. Transformer
C. Fuse
D. Ground Fault Circuit Interrupter (GFCI)
Rationale: A GFCI monitors current flow and quickly disconnects the
circuit if it detects a difference between hot and neutral, indicating
leakage to ground.
5. In a three-phase system, the line-to-line voltage is 208 volts. What is
the line-to-neutral voltage?
A. 208 V
B. 120 V
C. 120 V
D. 240 V
Rationale: Line-to-neutral voltage in a 208V three-phase system is
calculated as 208 ÷ √3 ≈ 120 V.
6. What color is typically used for a grounding conductor in electrical
wiring?
A. Red
B. Green or bare copper
C. Black
D. White
Rationale: NEC specifies green or bare copper for grounding
conductors to clearly differentiate them from current-carrying wires.
7. Which tool is used to measure the resistance of electrical wiring?
A. Voltmeter
B. Ammeter
C. Ohmmeter
D. Clamp meter
Rationale: An ohmmeter measures resistance and continuity, which is
important for verifying wiring integrity.
8. Which of the following is considered a hazardous location?
A. Dry office space
B. Area with flammable gases
C. Standard residential garage
D. Public hallway
Rationale: Hazardous locations are defined as areas where explosive
, gases, vapors, or dust may be present, requiring special wiring and
equipment.
9. What is the purpose of a conduit in electrical installations?
A. Increase voltage
B. Store electrical energy
C. Protect and route electrical wiring
D. Act as a fuse
Rationale: Conduits provide physical protection, prevent accidental
contact, and organize wiring in residential, commercial, and industrial
installations.
10. Which type of transformer is commonly used to step down
voltage for residential use?
A. Isolation transformer
B. Single-phase transformer
C. Autotransformer
D. Three-phase transformer
Rationale: Single-phase transformers are used to reduce utility voltage
(e.g., 240V) to standard residential levels (120/240V).
11. What is the typical amperage rating of a residential branch circuit
for lighting?
A. 50 A
B. 40 A
C. 15 A or 20 A
D. 30 A
Rationale: Residential lighting circuits are typically protected with 15-
or 20-amp breakers according to NEC guidelines.
12. Which conductor is considered the “neutral” in a 120/240V
residential circuit?
A. Black
B. White
C. Green
D. Red
Rationale: The white conductor serves as the neutral, providing a
return path for current and completing the circuit safely.
13. When installing a three-way switch, what is the purpose of the
traveler wires?
A. Carry neutral current
Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary purpose of a circuit breaker in an electrical
system?
A. Increase voltage
B. Store energy
C. Protect circuits from overcurrent
D. Measure current
Rationale: Circuit breakers are designed to interrupt current flow in
the event of overloads or short circuits, preventing damage to wiring
and equipment.
2. Which type of wiring is most commonly used for residential interior
wiring?
A. Aluminum conduit
B. Non-metallic sheathed cable (NM)
C. Rigid metal conduit (RMC)
D. Flexible metal conduit
Rationale: NM cable, often called Romex, is widely used in residential
wiring due to its ease of installation and suitability for dry locations.
3. The National Electrical Code (NEC) requires that all 15- and 20-
ampere, 120-volt branch circuits have what type of grounding?
A. Optional
B. Metallic conduit only
C. Equipment grounding conductor
D. Grounding is not required
Rationale: NEC mandates an equipment grounding conductor for
safety to prevent electrical shock and ensure proper operation of
overcurrent protection devices.
,4. Which device is used to detect and protect against ground faults?
A. Circuit breaker
B. Transformer
C. Fuse
D. Ground Fault Circuit Interrupter (GFCI)
Rationale: A GFCI monitors current flow and quickly disconnects the
circuit if it detects a difference between hot and neutral, indicating
leakage to ground.
5. In a three-phase system, the line-to-line voltage is 208 volts. What is
the line-to-neutral voltage?
A. 208 V
B. 120 V
C. 120 V
D. 240 V
Rationale: Line-to-neutral voltage in a 208V three-phase system is
calculated as 208 ÷ √3 ≈ 120 V.
6. What color is typically used for a grounding conductor in electrical
wiring?
A. Red
B. Green or bare copper
C. Black
D. White
Rationale: NEC specifies green or bare copper for grounding
conductors to clearly differentiate them from current-carrying wires.
7. Which tool is used to measure the resistance of electrical wiring?
A. Voltmeter
B. Ammeter
C. Ohmmeter
D. Clamp meter
Rationale: An ohmmeter measures resistance and continuity, which is
important for verifying wiring integrity.
8. Which of the following is considered a hazardous location?
A. Dry office space
B. Area with flammable gases
C. Standard residential garage
D. Public hallway
Rationale: Hazardous locations are defined as areas where explosive
, gases, vapors, or dust may be present, requiring special wiring and
equipment.
9. What is the purpose of a conduit in electrical installations?
A. Increase voltage
B. Store electrical energy
C. Protect and route electrical wiring
D. Act as a fuse
Rationale: Conduits provide physical protection, prevent accidental
contact, and organize wiring in residential, commercial, and industrial
installations.
10. Which type of transformer is commonly used to step down
voltage for residential use?
A. Isolation transformer
B. Single-phase transformer
C. Autotransformer
D. Three-phase transformer
Rationale: Single-phase transformers are used to reduce utility voltage
(e.g., 240V) to standard residential levels (120/240V).
11. What is the typical amperage rating of a residential branch circuit
for lighting?
A. 50 A
B. 40 A
C. 15 A or 20 A
D. 30 A
Rationale: Residential lighting circuits are typically protected with 15-
or 20-amp breakers according to NEC guidelines.
12. Which conductor is considered the “neutral” in a 120/240V
residential circuit?
A. Black
B. White
C. Green
D. Red
Rationale: The white conductor serves as the neutral, providing a
return path for current and completing the circuit safely.
13. When installing a three-way switch, what is the purpose of the
traveler wires?
A. Carry neutral current
