ELECTRICAL CONTRACTOR LICENSE EXAM
PRACTICE TEST QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2025 Q&A | INSTANT
DOWNLOAD PDF
1. What is the minimum size grounding electrode conductor for a 200-
amp service using copper?
A. 2 AWG
B. 4 AWG
C. 6 AWG
D. 8 AWG
The NEC Table 250.66 requires a 4 AWG copper conductor for a 200-amp
service.
2. Which of the following is required for all underground service
conductors?
A. Aluminum wiring
B. Conduit protection
,C. Aerial support
D. Weatherproof enclosures
Underground conductors must be protected by approved raceways or
conduit to avoid physical damage.
3. In residential wiring, what is the standard voltage supplied to most
homes in the U.S.?
A. 208/120V
B. 240/120V
C. 277/480V
D. 120V only
Typical residential service includes two 120V legs creating a 240V total
service.
4. What is the color code for the ground wire in residential wiring?
A. Black
B. Red
C. Green or bare
D. White
NEC requires ground wires to be either green or bare copper.
5. A 20-amp circuit must use a minimum of what size copper conductor?
A. 16 AWG
B. 18 AWG
,C. 12 AWG
D. 10 AWG
Per NEC 210.19(A)(4), 20-amp circuits must use a minimum of 12 AWG
copper wire.
6. How often must electrical contractor licenses typically be renewed in
most states?
A. Every 10 years
B. Every 2 to 3 years
C. Annually
D. Never
Many jurisdictions require license renewal every 2 to 3 years to ensure
continued competency.
7. Which of the following requires GFCI protection?
A. Bedroom outlets
B. Bathroom outlets
C. Living room outlets
D. Basement lighting
GFCI protection is required in wet locations, such as bathrooms, per NEC
210.8.
8. What is the function of an overcurrent protection device?
A. Increases current flow
B. Prevents wire overheating
, C. Stabilizes voltage
D. Amplifies power
OCPDs like breakers and fuses prevent wires from overheating due to
excessive current.
9. In a commercial setting, what is the required height for mounting a
wall switch?
A. 36 inches
B. 42 inches
C. 48 inches
D. 60 inches
Per ADA and NEC standards, switches are usually mounted at 48 inches
maximum from the floor.
10. Which type of drawing is typically used to show the overall
layout of a building's electrical system?
A. Schematic diagram
B. Plan view (floor plan)
C. Riser diagram
D. Elevation drawing
Plan view diagrams show the location of devices, wiring, and panels across
the floor layout.
11. Which of the following can be used as a grounding electrode?
PRACTICE TEST QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2025 Q&A | INSTANT
DOWNLOAD PDF
1. What is the minimum size grounding electrode conductor for a 200-
amp service using copper?
A. 2 AWG
B. 4 AWG
C. 6 AWG
D. 8 AWG
The NEC Table 250.66 requires a 4 AWG copper conductor for a 200-amp
service.
2. Which of the following is required for all underground service
conductors?
A. Aluminum wiring
B. Conduit protection
,C. Aerial support
D. Weatherproof enclosures
Underground conductors must be protected by approved raceways or
conduit to avoid physical damage.
3. In residential wiring, what is the standard voltage supplied to most
homes in the U.S.?
A. 208/120V
B. 240/120V
C. 277/480V
D. 120V only
Typical residential service includes two 120V legs creating a 240V total
service.
4. What is the color code for the ground wire in residential wiring?
A. Black
B. Red
C. Green or bare
D. White
NEC requires ground wires to be either green or bare copper.
5. A 20-amp circuit must use a minimum of what size copper conductor?
A. 16 AWG
B. 18 AWG
,C. 12 AWG
D. 10 AWG
Per NEC 210.19(A)(4), 20-amp circuits must use a minimum of 12 AWG
copper wire.
6. How often must electrical contractor licenses typically be renewed in
most states?
A. Every 10 years
B. Every 2 to 3 years
C. Annually
D. Never
Many jurisdictions require license renewal every 2 to 3 years to ensure
continued competency.
7. Which of the following requires GFCI protection?
A. Bedroom outlets
B. Bathroom outlets
C. Living room outlets
D. Basement lighting
GFCI protection is required in wet locations, such as bathrooms, per NEC
210.8.
8. What is the function of an overcurrent protection device?
A. Increases current flow
B. Prevents wire overheating
, C. Stabilizes voltage
D. Amplifies power
OCPDs like breakers and fuses prevent wires from overheating due to
excessive current.
9. In a commercial setting, what is the required height for mounting a
wall switch?
A. 36 inches
B. 42 inches
C. 48 inches
D. 60 inches
Per ADA and NEC standards, switches are usually mounted at 48 inches
maximum from the floor.
10. Which type of drawing is typically used to show the overall
layout of a building's electrical system?
A. Schematic diagram
B. Plan view (floor plan)
C. Riser diagram
D. Elevation drawing
Plan view diagrams show the location of devices, wiring, and panels across
the floor layout.
11. Which of the following can be used as a grounding electrode?
