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Rationales 2026 Q&A | Instant Download Pdf
1. What is the minimum size copper grounding electrode conductor required for
a 200-amp residential service?
A. 6 AWG
B. 4 AWG
C. 2 AWG
D. 8 AWG
Rationale: NEC Table 250.66 specifies a 4 AWG copper conductor for 2/0 AWG
copper service-entrance conductors (typical for 200A).
2. How often should receptacles in a commercial office be placed along a wall
line?
A. Every 8 feet
B. Every 10 feet
C. Every 12 feet
D. Every 16 feet
Rationale: NEC 210.52(A)(1) requires receptacles so that no point is more than 6
feet from one, effectively one every 12 feet.
3. What color is typically used for the grounded (neutral) conductor?
A. Green
B. White or gray
C. Red
D. Blue
Rationale: NEC 200.6 requires neutrals to be identified with white or gray
insulation.
,4. In a 120/240V single-phase panel, which bus bars must be connected to
create a 240V circuit?
A. Two circuits on the same leg
B. Two circuits on opposite legs
C. Two circuits on neutral
D. Two circuits on the ground
Rationale: 240V requires both hot legs (L1 and L2) that are 180° out of phase.
5. What is the voltage between the neutral and ground in a properly functioning
circuit?
A. 5V
B. 2V
C. 0V
D. 10V
Rationale: Neutral and ground are bonded at one point (main panel), so potential
difference is ideally 0V.
6. What is the minimum burial depth for direct-buried Type UF cable under a
residential yard?
A. 6 inches
B. 12 inches
C. 24 inches
D. 30 inches
Rationale: NEC Table 300.5 specifies 24 inches minimum for direct burial under
residential property.
7. What type of conduit is best for corrosive environments?
A. EMT
B. IMC
, C. PVC (Schedule 80)
D. RMC
Rationale: PVC conduit resists moisture and corrosion, making it ideal for damp or
corrosive locations.
8. Which conductor is required to be continuous without splices?
A. Hot
B. Neutral
C. Grounding electrode conductor
D. Equipment grounding conductor
Rationale: NEC 250.64(C) requires the grounding electrode conductor to be
continuous unless irreversible connections are used.
9. The total load on a 20A, 120V branch circuit should not exceed:
A. 1800W
B. 1920W
C. 2000W
D. 2400W
Rationale: Continuous loads are limited to 80% of circuit rating — 0.8 × 20A ×
120V = 1920W.
10. What is the standard ampacity of a 12 AWG copper conductor?
A. 25A
B. 20A
C. 15A
D. 30A
Rationale: NEC Table 310.16 lists 20A for 12 AWG copper conductors rated at 60°C
insulation (general purpose).
11. Where are arc-fault circuit interrupters (AFCIs) required in a dwelling?