IAEI Master Electrical Inspector
Examination Practice Questions And
Correct Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
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1. What is the primary purpose of a ground fault circuit interrupter
(GFCI)?
A. Protect equipment from overcurrent
B. Protect people from electric shock
C. Reduce energy consumption
D. Prevent short circuits
Rationale: GFCIs are designed to quickly disconnect power when a
ground fault is detected, protecting humans from electric shock.
2. In a residential dwelling, what is the minimum branch-circuit rating
required for a kitchen countertop receptacle?
, A. 15 amperes
B. 20 amperes
C. 30 amperes
D. 10 amperes
Rationale: NEC requires at least two 20-ampere small appliance
branch circuits for kitchen countertops.
3. Which type of wiring method is suitable for wet locations?
A. NM cable
B. THWN conductors in conduit
C. UF cable
D. Nonmetallic sheathed cable
Rationale: THWN conductors are rated for wet locations, making
them suitable for conduits in such environments.
4. What is the maximum number of 90°C rated conductors allowed in a
raceway before derating is required?
A. 3
B. 6
C. 9
D. More than 3
Rationale: NEC requires derating when more than three current-
carrying conductors are installed in a raceway.
5. In a commercial building, how often should emergency lighting be
tested?
, A. Daily
B. Weekly
C. Monthly
D. Annually
Rationale: NEC and NFPA 101 require emergency lighting to be tested
monthly to ensure proper operation.
6. What is the minimum conductor size for a 100-ampere service using
copper conductors?
A. 2 AWG
B. 3/0 AWG
C. 1 AWG
D. 4/0 AWG
Rationale: NEC Table 310.15 specifies 3/0 AWG copper conductors for
a 100-ampere service under typical conditions.
7. Which of the following is NOT a recognized type of overcurrent
protection?
A. Fuses
B. Circuit breakers
C. Switches
D. Molded-case breakers
Rationale: Switches are devices to make or break a circuit; they do
not provide overcurrent protection.
, 8. For a feeder supplying a commercial building, what is the minimum
ampacity of the conductors if the calculated load is 120 A?
A. 100 A
B. 115 A
C. 125 A
D. 150 A
Rationale: NEC requires the conductor ampacity to be equal to or
greater than the calculated load.
9. What is the maximum voltage drop recommended for feeders and
branch circuits to ensure efficient operation?
A. 2%
B. 3%
C. 5%
D. 10%
Rationale: NEC recommends that the combined voltage drop on
feeders and branch circuits not exceed 5% for optimal performance.
10. Which type of receptacle is required in a bathroom?
A. Standard 15 A
B. GFCI protected
C. AFCI protected
D. Weather-resistant
Rationale: NEC requires all bathroom receptacles to be GFCI
protected due to the presence of water.
Examination Practice Questions And
Correct Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
1. What is the primary purpose of a ground fault circuit interrupter
(GFCI)?
A. Protect equipment from overcurrent
B. Protect people from electric shock
C. Reduce energy consumption
D. Prevent short circuits
Rationale: GFCIs are designed to quickly disconnect power when a
ground fault is detected, protecting humans from electric shock.
2. In a residential dwelling, what is the minimum branch-circuit rating
required for a kitchen countertop receptacle?
, A. 15 amperes
B. 20 amperes
C. 30 amperes
D. 10 amperes
Rationale: NEC requires at least two 20-ampere small appliance
branch circuits for kitchen countertops.
3. Which type of wiring method is suitable for wet locations?
A. NM cable
B. THWN conductors in conduit
C. UF cable
D. Nonmetallic sheathed cable
Rationale: THWN conductors are rated for wet locations, making
them suitable for conduits in such environments.
4. What is the maximum number of 90°C rated conductors allowed in a
raceway before derating is required?
A. 3
B. 6
C. 9
D. More than 3
Rationale: NEC requires derating when more than three current-
carrying conductors are installed in a raceway.
5. In a commercial building, how often should emergency lighting be
tested?
, A. Daily
B. Weekly
C. Monthly
D. Annually
Rationale: NEC and NFPA 101 require emergency lighting to be tested
monthly to ensure proper operation.
6. What is the minimum conductor size for a 100-ampere service using
copper conductors?
A. 2 AWG
B. 3/0 AWG
C. 1 AWG
D. 4/0 AWG
Rationale: NEC Table 310.15 specifies 3/0 AWG copper conductors for
a 100-ampere service under typical conditions.
7. Which of the following is NOT a recognized type of overcurrent
protection?
A. Fuses
B. Circuit breakers
C. Switches
D. Molded-case breakers
Rationale: Switches are devices to make or break a circuit; they do
not provide overcurrent protection.
, 8. For a feeder supplying a commercial building, what is the minimum
ampacity of the conductors if the calculated load is 120 A?
A. 100 A
B. 115 A
C. 125 A
D. 150 A
Rationale: NEC requires the conductor ampacity to be equal to or
greater than the calculated load.
9. What is the maximum voltage drop recommended for feeders and
branch circuits to ensure efficient operation?
A. 2%
B. 3%
C. 5%
D. 10%
Rationale: NEC recommends that the combined voltage drop on
feeders and branch circuits not exceed 5% for optimal performance.
10. Which type of receptacle is required in a bathroom?
A. Standard 15 A
B. GFCI protected
C. AFCI protected
D. Weather-resistant
Rationale: NEC requires all bathroom receptacles to be GFCI
protected due to the presence of water.
