IAEI Master Electrical Inspector
Examination Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
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1. What is the primary purpose of the National Electrical Code (NEC)?
A. To limit electrical innovation
B. To provide safe electrical installation standards
C. To reduce electricity bills
D. To standardize electrical pricing
Rationale: The NEC is designed to ensure the safety of electrical
installations and protect people and property.
2. Which type of wiring method is typically required in commercial
buildings for exposed runs?
A. NM cable
, B. EMT conduit
C. UF cable
D. BX cable
Rationale: Exposed wiring in commercial buildings commonly uses
EMT conduit because of its durability and protection.
3. What is the maximum number of 15-ampere branch circuits permitted
to supply a single receptacle outlet in a dwelling unit according to
NEC?
A. 1
B. 2
C. 3
D. 4
Rationale: NEC limits a single receptacle outlet to two 15-ampere
branch circuits to prevent overloading.
4. In a 3-phase, 4-wire wye system, what is the voltage between any two
phase conductors if the phase voltage is 208V?
A. 208V
B. 208/√3 V
C. 360V
D. 480V
Rationale: Line-to-line voltage in a wye system is V_L = V_Phase × √3,
so 208 × 1.732 ≈ 360V.
,5. Which conductor is required for bonding metal water piping to the
grounding system?
A. Aluminum conductor
B. Copper conductor
C. Iron wire
D. Plastic wire
Rationale: NEC requires copper conductors for grounding/bonding
water piping to ensure conductivity and corrosion resistance.
6. What is the purpose of a GFCI (Ground Fault Circuit Interrupter)?
A. Prevent short circuits
B. Prevent overcurrent
C. Protect against ground faults and shock
D. Increase voltage stability
Rationale: GFCIs detect leakage currents to ground and interrupt
power to prevent electric shock.
7. Which article in the NEC covers Low-Voltage Lighting Systems?
A. 210
B. 220
C. 411
D. 450
Rationale: Article 411 specifically covers low-voltage lighting systems
like 30V and 150V circuits.
, 8. When installing a feeder in a commercial building, which conductor is
sized based on the highest load?
A. Neutral conductor
B. Phase conductor
C. Grounding conductor
D. Jumper conductor
Rationale: Feeders must be sized according to the maximum
expected load carried by the phase conductors.
9. What is the minimum height for mounting a wall receptacle in a
commercial space?
A. 12 inches
B. 24 inches
C. 15 inches
D. 18 inches
Rationale: NEC specifies a minimum mounting height of 15 inches
above the finished floor for general-purpose receptacles.
10. Which device provides short-circuit and overload protection for
a branch circuit?
A. Fuse
B. Circuit breaker
C. GFCI
D. Transformer
Examination Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of the National Electrical Code (NEC)?
A. To limit electrical innovation
B. To provide safe electrical installation standards
C. To reduce electricity bills
D. To standardize electrical pricing
Rationale: The NEC is designed to ensure the safety of electrical
installations and protect people and property.
2. Which type of wiring method is typically required in commercial
buildings for exposed runs?
A. NM cable
, B. EMT conduit
C. UF cable
D. BX cable
Rationale: Exposed wiring in commercial buildings commonly uses
EMT conduit because of its durability and protection.
3. What is the maximum number of 15-ampere branch circuits permitted
to supply a single receptacle outlet in a dwelling unit according to
NEC?
A. 1
B. 2
C. 3
D. 4
Rationale: NEC limits a single receptacle outlet to two 15-ampere
branch circuits to prevent overloading.
4. In a 3-phase, 4-wire wye system, what is the voltage between any two
phase conductors if the phase voltage is 208V?
A. 208V
B. 208/√3 V
C. 360V
D. 480V
Rationale: Line-to-line voltage in a wye system is V_L = V_Phase × √3,
so 208 × 1.732 ≈ 360V.
,5. Which conductor is required for bonding metal water piping to the
grounding system?
A. Aluminum conductor
B. Copper conductor
C. Iron wire
D. Plastic wire
Rationale: NEC requires copper conductors for grounding/bonding
water piping to ensure conductivity and corrosion resistance.
6. What is the purpose of a GFCI (Ground Fault Circuit Interrupter)?
A. Prevent short circuits
B. Prevent overcurrent
C. Protect against ground faults and shock
D. Increase voltage stability
Rationale: GFCIs detect leakage currents to ground and interrupt
power to prevent electric shock.
7. Which article in the NEC covers Low-Voltage Lighting Systems?
A. 210
B. 220
C. 411
D. 450
Rationale: Article 411 specifically covers low-voltage lighting systems
like 30V and 150V circuits.
, 8. When installing a feeder in a commercial building, which conductor is
sized based on the highest load?
A. Neutral conductor
B. Phase conductor
C. Grounding conductor
D. Jumper conductor
Rationale: Feeders must be sized according to the maximum
expected load carried by the phase conductors.
9. What is the minimum height for mounting a wall receptacle in a
commercial space?
A. 12 inches
B. 24 inches
C. 15 inches
D. 18 inches
Rationale: NEC specifies a minimum mounting height of 15 inches
above the finished floor for general-purpose receptacles.
10. Which device provides short-circuit and overload protection for
a branch circuit?
A. Fuse
B. Circuit breaker
C. GFCI
D. Transformer
