What correction factor is applied at 35°C for THHN insulation?

For THHN insulation, the correction factor at 35°C is important for accurately calculating the ampacity of wires. At elevated temperatures, the ampacity of conductors decreases, which necessitates applying a correction factor to ensure safe and efficient electrical system design.

The correct correction factor of 0.96 is derived from the National Electrical Code (NEC), which provides adjustment factors for different temperature ratings. At 35°C, THHN insulated conductors are able to carry slightly less current than they would at the standard temperature (typically 30°C).

This factor considers thermal characteristics and the material's ability to handle electrical load without overheating. Therefore, using 0.96 allows for a more accurate assessment of the conductor’s capacity, promoting safety in electrical applications by preventing overheating and potential failures due to excessive current.

The other options provide incorrect values that do not align with the NEC guidelines for THHN cable at this specific temperature.