Electrician's Licensing Practice Exam

What information do NEC Tables 310-10 through 310-21 provide?

1. Sizes of copper and aluminum wire

2. Grounding requirements for AC systems

3. Types of conduit materials

4. Specifications for circuit breakers

The correct answer is: Sizes of copper and aluminum wire

The tables in the National Electrical Code (NEC) ranging from 310-10 through 310-21 provide critical information regarding the ampacity of conductors, specifically detailing the sizes of copper and aluminum wires. Ampacity indicates the maximum amount of electric current a conductor or device can carry before sustaining immediate or progressive deterioration. These tables take into account various factors such as insulation type, temperature ratings, and installation conditions to ensure safe and effective electrical installations. Understanding the specifications laid out in these tables is essential for electricians when calculating the appropriate wire sizes for different electrical installations to prevent overheating and ensure compliance with safety codes. The other options relate to different aspects of electrical installations: grounding requirements, conduit materials, and circuit breaker specifications, none of which are covered by the specified NEC tables. Therefore, the focus on wire sizes is the key reason this answer is the most appropriate.