Examination Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
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1. What is the minimum size copper grounding electrode conductor for a
200-amp residential service?
A. 6 AWG
B. 4 AWG
C. 2 AWG
D. 8 AWG
Rationale: According to NEC Table 250.66, a 200-amp service requires
a minimum 4 AWG copper grounding electrode conductor.
2. Which type of wiring method is commonly used in residential
construction for interior walls?
, A. BX Cable
B. UF Cable
C. NM Cable (Romex)
D. MC Cable
Rationale: NM (Nonmetallic-sheathed) cable is standard for interior
residential wiring in walls.
3. What is the maximum number of 15-amp receptacles allowed on a 20-
amp general-purpose branch circuit?
A. 8
B. 10
C. 12
D. 15
Rationale: The NEC allows a maximum of 10 receptacles on a 20-amp
general-use circuit, considering the 180 VA per receptacle rule.
4. In a dwelling unit, which area requires at least one 20-amp circuit
dedicated to receptacles?
A. Bedroom
B. Kitchen countertop
C. Living room
D. Bathroom
Rationale: NEC 210.11(C)(1) requires at least two 20-amp circuits for
kitchen countertop receptacles.
,5. Which of the following is the correct minimum height for a wall-
mounted receptacle in a kitchen?
A. 18 inches
B. 15 inches
C. 12 inches
D. 20 inches
Rationale: NEC 210.52(C) recommends receptacle outlets be placed
no more than 20 inches above the countertop, typically 15 inches is
standard for accessibility.
6. What is the maximum allowed voltage drop for branch circuits in a
residence?
A. 2%
B. 3%
C. 5%
D. 10%
Rationale: NEC recommends a maximum of 3% voltage drop for
branch circuits to ensure efficient operation of appliances.
7. What is the minimum distance a receptacle must be installed from a
sink in a dwelling bathroom?
A. 12 inches
B. 24 inches
C. 3 feet
D. 6 feet
, Rationale: NEC 210.8(A) requires GFCI-protected receptacles to be
installed within 3 feet of the outside edge of a bathroom sink.
8. Which device is required to protect 125-volt, single-phase, 15- and 20-
amp receptacles in dwelling bathrooms?
A. AFCI
B. GFCI
C. Surge protector
D. Circuit breaker only
Rationale: NEC 210.8(A) mandates GFCI protection for receptacles in
bathrooms.
9. What is the purpose of an AFCI in a residential circuit?
A. Protects against overcurrent
B. Protects against arc faults
C. Protects against lightning
D. Grounds the circuit
Rationale: AFCIs (Arc-Fault Circuit Interrupters) are designed to
prevent fires caused by arcing faults.
10. What is the minimum burial depth for a 120-volt underground
NM cable in residential yards?
A. 6 inches
B. Not allowed
C. 12 inches
D. 18 inches