23 questions · 16% of the NEC Knowledge exam
Exam tip
Be aware of the specific fill requirements for different types of systems to ensure compliance.
Why B is correct
According to 2026 NFPA 70 NEC Article 336.2(A), the maximum allowable conductor fill percentage for 3-phase, 4-wire systems is 50%. The other options exceed the code requirements.
Exam tip
Be aware of the specific fill ratio requirements for different types of raceways and conductor sizes.
Why C is correct
According to 2026 NEC 318.17(A), the minimum allowable fill ratio for a 100A, 480V branch circuit in a raceway is 80%. The other options do not meet the NEC requirements.
Exam tip
Special equipment such as life support systems often have specific code requirements for conductor sizing to ensure safety and reliability.
Why B is correct
According to 2026 NEC Article 680.41(A), the minimum conductor size for a 480V, 3-phase motor circuit for a life support system is 8 AWG. Larger conductors are not required for this application.
Exam tip
Medical equipment often requires specific conductor size requirements to ensure proper operation and safety.
Why B is correct
According to 2026 NEC 210.11(B), a 50A, 208V branch circuit for medical equipment requires a minimum conductor size of 12 AWG. The other options are not suitable for this application.
Exam tip
Always check the specific requirements for kitchen circuits, as they often have different conductor size requirements.
Why A is correct
According to 2026 NFPA 70 NEC Article 210.21(B)(1), the minimum conductor size for a 20-ampere branch circuit in a kitchen is 10 AWG. The other options are larger sizes typically used for different applications.
Exam tip
Always check the specific requirements for kitchen circuits as they often have different conductor size requirements.
Why B is correct
According to 2026 NEC Article 210.16(A), the minimum conductor size for a 20A branch circuit in a kitchen is 12 AWG. The other options are not suitable for this application.
Exam tip
When dealing with feeders, it is important to refer to specific tables in the NEC to determine the correct conductor size.
Why C is correct
According to 2026 NEC Article 310.15(B)(16), the minimum conductor size for a 600V, 3-phase feeder with a 1200A load is 350 kcmil. Larger conductors are not required for this application.
Exam tip
Outdoor installations often have specific conductor size requirements to protect against environmental factors such as moisture and temperature.
Why A is correct
According to 2026 NEC Article 310.15(B)(16), the minimum conductor size for a 15A branch circuit installed outdoors is 12 AWG. Larger conductors are not required for this application.
Exam tip
Be familiar with the specific conductor requirements for different types of facilities.
Why D is correct
According to 2026 NFPA 70 NEC Article 725.140(A), Type THWN-2 conductors are required for patient care areas in healthcare facilities. The other options are not specified for this application.
Exam tip
Ensure that the conductor rating is appropriate for the voltage and current requirements of the motor circuit.
Why C is correct
According to 2026 NEC 310.15(B)(16), a 60A, 480V motor circuit requires a conductor with a minimum rating of 1500V. The other options are not suitable for this voltage and current rating.
Exam tip
Know the specific locations where AFCIs are required to ensure safety.
Why C is correct
According to 2026 NFPA 70 NEC Article 210.12(A), crawl spaces are exempt from the requirement for AFCIs. Bedrooms, living rooms, and garages are not exempt and must have AFCIs installed where required.
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