Electrician's Licensing Practice Exam

Which NEC tables provide information about wire sizing and temperature ratings?

1. Table 310

2. Table 450

3. Annex C1 and C2

4. Table 230

The correct answer is: Annex C1 and C2

The choice focused on is Annex C1 and C2, which indeed provides valuable information related to wire sizing and temperature ratings. These annexes are part of the National Electrical Code (NEC) and are essential resources for electricians and engineers to understand how to select appropriate conductors based on their current-carrying capacity and the ambient temperature conditions under which the wire will operate. Annex C1 lists the temperature ratings of conductors and helps users understand how these ratings affect the choice of wire for different environments. For example, it indicates the types of insulation used and their respective maximum temperature ratings. Annex C2 complements this by outlining the adjustment factors that may need to be considered based on the number of conductors installed together or the presence of heat sources. This inclusivity of information is critical when sizing conductors to ensure safety, efficiency, and compliance with the NEC standards. Such understanding of temperature ratings and their effect on wire sizing is vital for preventing overheating and potential fire hazards, making it a core aspect of electrical safety practices. In contrast, the other options focus on different areas; Table 310 primarily addresses the allowable ampacities of insulated conductors but does not provide the comprehensive temperature rating context that is available in Annex C. Table 450