CO Master Electrician Exam
Questions
And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A| Instant Download Pdf
1. What is the minimum size copper grounding electrode conductor
required for a 400-amp service?
A. 2 AWG
B. 4 AWG
C. 1/0 AWG
D. 2/0 AWG
Rationale: The NEC specifies 1/0 AWG copper for grounding electrode
conductors on 400-amp services.
2. What is the maximum number of 90° bends allowed in a single conduit
run between pull points?
A. Two
B. Three
C. Four
D. Five
Rationale: The total cumulative bends may not exceed 360° to permit
pulling of conductors.
3. The neutral conductor in a 120/240-volt single-phase service must be
sized based on:
A. The largest ungrounded conductor
,B. The calculated neutral load
C. The maximum unbalanced load
D. The service ampacity multiplied by 0.8
Rationale: Neutral sizing is determined by the unbalanced load.
4. What is the minimum burial depth for rigid metal conduit under a
residential driveway?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Rationale: RMC requires at least 18-inch burial under driveways.
5. A continuous load must be calculated at what percentage of its rating?
A. 80%
B. 125%
C. 100%
D. 150%
Rationale: Continuous loads must be sized at 125% for safety and heat
considerations.
6. What type of circuit is required for kitchen countertop receptacles?
A. 15-amp general-purpose
B. Multi-wire branch circuit
C. Two or more 20-amp small-appliance branch circuits
D. Any circuit over 15 amps
Rationale: NEC requires at least two 20-amp SABCs for kitchen
countertops.
7. GFCI protection is required for which of the following?
A. Bedroom outlets
, B. Garage receptacles
C. Living room outlets
D. Hardwired ovens
Rationale: Garages require GFCI on all 125–250 V receptacles.
8. AFCI protection is required in which location?
A. Patio
B. Bathroom
C. Bedrooms
D. Detached garages
Rationale: Bedrooms require AFCI protection for fire prevention.
9. The maximum standard rating of an overcurrent device for #12 AWG
copper is:
A. 15 amps
B. 20 amps
C. 25 amps
D. 30 amps
Rationale: #12 copper is limited to 20 amps under NEC rules.
10. What is the demand factor for the first 10 kW of electric range load?
A. 25%
B. 40%
C. 100%
D. 80%
Rationale: First 10 kW of range load is taken at 100%.
11. Which conductor is permitted to be smaller than the ungrounded
conductors in a service?
A. Equipment grounding conductor
B. Grounding electrode conductor
C. Neutral conductor
Questions
And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A| Instant Download Pdf
1. What is the minimum size copper grounding electrode conductor
required for a 400-amp service?
A. 2 AWG
B. 4 AWG
C. 1/0 AWG
D. 2/0 AWG
Rationale: The NEC specifies 1/0 AWG copper for grounding electrode
conductors on 400-amp services.
2. What is the maximum number of 90° bends allowed in a single conduit
run between pull points?
A. Two
B. Three
C. Four
D. Five
Rationale: The total cumulative bends may not exceed 360° to permit
pulling of conductors.
3. The neutral conductor in a 120/240-volt single-phase service must be
sized based on:
A. The largest ungrounded conductor
,B. The calculated neutral load
C. The maximum unbalanced load
D. The service ampacity multiplied by 0.8
Rationale: Neutral sizing is determined by the unbalanced load.
4. What is the minimum burial depth for rigid metal conduit under a
residential driveway?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Rationale: RMC requires at least 18-inch burial under driveways.
5. A continuous load must be calculated at what percentage of its rating?
A. 80%
B. 125%
C. 100%
D. 150%
Rationale: Continuous loads must be sized at 125% for safety and heat
considerations.
6. What type of circuit is required for kitchen countertop receptacles?
A. 15-amp general-purpose
B. Multi-wire branch circuit
C. Two or more 20-amp small-appliance branch circuits
D. Any circuit over 15 amps
Rationale: NEC requires at least two 20-amp SABCs for kitchen
countertops.
7. GFCI protection is required for which of the following?
A. Bedroom outlets
, B. Garage receptacles
C. Living room outlets
D. Hardwired ovens
Rationale: Garages require GFCI on all 125–250 V receptacles.
8. AFCI protection is required in which location?
A. Patio
B. Bathroom
C. Bedrooms
D. Detached garages
Rationale: Bedrooms require AFCI protection for fire prevention.
9. The maximum standard rating of an overcurrent device for #12 AWG
copper is:
A. 15 amps
B. 20 amps
C. 25 amps
D. 30 amps
Rationale: #12 copper is limited to 20 amps under NEC rules.
10. What is the demand factor for the first 10 kW of electric range load?
A. 25%
B. 40%
C. 100%
D. 80%
Rationale: First 10 kW of range load is taken at 100%.
11. Which conductor is permitted to be smaller than the ungrounded
conductors in a service?
A. Equipment grounding conductor
B. Grounding electrode conductor
C. Neutral conductor
