CO Class E Electrical Contractor
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A| Instant Download Pdf
1. What is the minimum burial depth for nonmetallic underground
conduit under residential driveways?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Rationale: NEC requires 18-inch cover for nonmetallic raceways under
residential driveways.
2. Equipment grounding conductor size is based on which factor?
A. Temperature rating
B. Rating of the overcurrent device
C. Length of conductor
D. Type of insulation
Rationale: EGC size comes from NEC Table 250.122 based on the OCPD
rating.
3. Which conductor is required to be grounded?
A. Phase conductor
B. Controller conductor
,C. Neutral conductor
D. Switch leg
Rationale: The neutral is the grounded conductor in electrical systems.
4. Maximum number of 90° bends allowed between pull points in a
conduit run?
A. 180°
B. 360°
C. 270°
D. 450°
Rationale: NEC limits total bends to 360° to ease wire pulling and reduce
insulation damage.
5. Minimum working clearance in front of a 120/240 V residential panel?
A. 24 inches
B. 36 inches
C. 30 inches
D. 48 inches
Rationale: NEC 110.26 requires 3 ft (36 inches) clearance for panels up to
600 V.
6. Maximum cord length for a garbage disposal?
A. 12 inches
B. 36 inches
C. 48 inches
D. 60 inches
Rationale: NEC Appliance rules limit disposal cords to 4 ft.
, 7. What type of GFCI protection is required for bathroom receptacles?
A. None
B. Weather-resistant
C. Class A GFCI
D. Tamper-resistant
Rationale: Bathrooms require GFCI protection; Class A is standard.
8. Minimum size copper grounding electrode conductor to a ground rod?
A. 14 AWG
B. 10 AWG
C. 6 AWG
D. 4 AWG
Rationale: NEC allows minimum 6 AWG copper to ground rods regardless
of service size.
9. A 20-amp small appliance branch circuit must use which wire size?
A. 16 AWG
B. 12 AWG
C. 10 AWG
D. 14 AWG
Rationale: 20A circuits require 12 AWG copper.
10. Outdoor service disconnects must be rated at least?
A. 15A
B. 60A
C. 100A
D. 200A
Rationale: NEC requires a minimum service disconnect rating of 100 amps
for dwellings.
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A| Instant Download Pdf
1. What is the minimum burial depth for nonmetallic underground
conduit under residential driveways?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Rationale: NEC requires 18-inch cover for nonmetallic raceways under
residential driveways.
2. Equipment grounding conductor size is based on which factor?
A. Temperature rating
B. Rating of the overcurrent device
C. Length of conductor
D. Type of insulation
Rationale: EGC size comes from NEC Table 250.122 based on the OCPD
rating.
3. Which conductor is required to be grounded?
A. Phase conductor
B. Controller conductor
,C. Neutral conductor
D. Switch leg
Rationale: The neutral is the grounded conductor in electrical systems.
4. Maximum number of 90° bends allowed between pull points in a
conduit run?
A. 180°
B. 360°
C. 270°
D. 450°
Rationale: NEC limits total bends to 360° to ease wire pulling and reduce
insulation damage.
5. Minimum working clearance in front of a 120/240 V residential panel?
A. 24 inches
B. 36 inches
C. 30 inches
D. 48 inches
Rationale: NEC 110.26 requires 3 ft (36 inches) clearance for panels up to
600 V.
6. Maximum cord length for a garbage disposal?
A. 12 inches
B. 36 inches
C. 48 inches
D. 60 inches
Rationale: NEC Appliance rules limit disposal cords to 4 ft.
, 7. What type of GFCI protection is required for bathroom receptacles?
A. None
B. Weather-resistant
C. Class A GFCI
D. Tamper-resistant
Rationale: Bathrooms require GFCI protection; Class A is standard.
8. Minimum size copper grounding electrode conductor to a ground rod?
A. 14 AWG
B. 10 AWG
C. 6 AWG
D. 4 AWG
Rationale: NEC allows minimum 6 AWG copper to ground rods regardless
of service size.
9. A 20-amp small appliance branch circuit must use which wire size?
A. 16 AWG
B. 12 AWG
C. 10 AWG
D. 14 AWG
Rationale: 20A circuits require 12 AWG copper.
10. Outdoor service disconnects must be rated at least?
A. 15A
B. 60A
C. 100A
D. 200A
Rationale: NEC requires a minimum service disconnect rating of 100 amps
for dwellings.
