Questions And Correct Answers
(Verified Answers) Plus Rationale2026
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1.
What is the minimum size grounding electrode conductor for a 200-amp service using copper?
A. 4 AWG
B. 6 AWG
C. 2 AWG
D. 1/0 AWG
Rationale: NEC Table 250.66 requires 2 AWG copper for 1/0–3/0 copper service conductors
(200A typical).
2.
The working clearance in front of 480V electrical equipment must be at least:
A. 2 ft
B. 3 ft
C. 4 ft
D. 6 ft
Rationale: NEC 110.26(A)(1) specifies 3 ft for 0–600V equipment.
3.
A continuous load on a branch circuit must be calculated at:
A. 80%
B. 125%
C. 150%
D. 100%
Rationale: NEC requires OCPD sizing at 125% of continuous load.
4.
The maximum number of 120V, 20-amp receptacles permitted on a general-purpose branch
circuit in a commercial setting is based on:
,A. 10 VA per receptacle
B. 180 VA per receptacle
C. 250 VA per receptacle
D. Unlimited
Rationale: NEC 220.14(I) assigns 180 VA per strap.
5.
What is the minimum burial depth for rigid metal conduit under a driveway?
A. 6 in
B. 12 in
C. 18 in
D. 24 in
Rationale: NEC Table 300.5 requires 18 in for RMC under driveways.
6.
A 3-phase, 4-wire wye system has a line-to-neutral voltage of 277V. The line-to-line voltage is:
A. 120V
B. 208V
C. 480V
D. 600V
Rationale: √3 × 277 ≈ 480V.
7.
What is the maximum cord length for a garbage disposal?
A. 1 ft
B. 2 ft
C. 4 ft
D. 6 ft
Rationale: NEC 422.16(B)(1) allows up to 4 ft.
8.
The grounded conductor must be identified by:
A. Red
B. Blue
C. White or gray
D. Green
Rationale: NEC 200.6 requires white or gray.
9.
What is the required rating for a service disconnect on a 400A service?
A. 200A
, B. 250A
C. 300A
D. 400A
Rationale: The disconnect must not be less than the service rating.
10.
PVC conduit exposed to sunlight must be:
A. Insulated
B. Buried
C. Sunlight resistant
D. Painted
Rationale: NEC requires sunlight resistance marking.
11.
In dwelling units, required receptacles in bedrooms must be placed so that no point is more than:
A. 3 ft from a receptacle
B. 4 ft
C. 6 ft
D. 10 ft
Rationale: NEC 210.52(A)(1) requires spacing so 6 ft from any point.
12.
What is the maximum voltage drop recommended for a branch circuit?
A. 1%
B. 3%
C. 5%
D. 10%
Rationale: NEC Informational Note recommends 3% max.
13.
What type of circuit is required for electric water heaters?
A. Multiwire branch circuit
B. Dedicated branch circuit
C. GFCI circuit
D. AFCI circuit
Rationale: Water heaters require a dedicated 240V circuit.
14.