14 questions · 10% of the NEC Knowledge exam
Exam tip
Always refer to the specific requirements for grounding electrode conductor sizes in the NEC.
Why B is correct
According to 2026 NEC Article 250.66(A), the minimum grounding electrode conductor size for a 120/240V, 3-phase, 4-wire service is 8 AWG. The correct answer is 8 AWG.
Exam tip
Remember the conduit fill calculations apply to raceways as well.
Why B is correct
The 2026 NEC Article 318.10(A) allows for a maximum fill of 70% for conductors in raceways. The 60%, 80%, and 90% options are incorrect as they exceed the maximum fill.
Exam tip
Always check the conduit fill tables in the NEC for the correct number of conductors.
Why C is correct
According to 2026 NEC Article 318.10, 1-inch rigid metal conduit can contain 15 12-gauge conductors at 80% fill. The correct answer is 15 conductors.
Exam tip
Remember that conduit fill calculations are based on the size of the conduit and the number of conductors.
Why C is correct
The 2026 NEC Article 318.10(A) allows for a maximum fill of 70% for conductors in raceways. The 50% and 60% options are incorrect as they are not allowed by the code, and the 80% option exceeds the maximum fill.
Exam tip
Understand the specific requirements for AFCI installation locations as outlined in the NEC.
Why B is correct
According to 2026 NEC Article 210.12(B), AFCIs must be installed at the circuit breaker panel in all bedroom circuits. The correct answer is At the circuit breaker panel.
Exam tip
Be familiar with the conduit fill tables in the NEC for various conduit types and sizes.
Why D is correct
According to 2026 NEC Article 318.10, 1-inch PVC conduit can contain 18 14-gauge conductors. The correct answer is 18 conductors.
Exam tip
Ensure that the grounding electrode conductor meets the minimum length requirements for proper grounding.
Why C is correct
The 2026 NEC Article 250.66(C) requires a minimum length of 20 feet for grounding electrode conductors from the service equipment to the grounding electrode. The other options are shorter than the code requirement.
Exam tip
Ensure you know the appropriate cable types for different voltage and application requirements.
Why A is correct
According to 2026 NEC Article 330.10, Type MC Cable is suitable for 480V, 3-phase, 4-wire systems in industrial facilities. The correct answer is Type MC Cable.
Exam tip
Always ensure proper ventilation in cable tray installations to prevent overheating.
Why B is correct
According to the 2026 NEC Article 318.104(B), the minimum spacing required between cable trays for proper ventilation is 12 inches. The other options are incorrect as they do not meet the code requirements.
Exam tip
Always check the minimum bend radius requirements for different types of conduits.
Why C is correct
The 2026 NEC Article 318.13 requires a minimum bend radius of 3 times the conduit diameter for RMC. The other options are incorrect as they do not meet the code requirements.
Answers and explanations for these are in the app.
Practice all 14 Wiring Methods & Materials questions
Plus timed mock exams and a wrong book that follows you between the web and the app.
Start studying free