What is the current-carrying capacity for No. 6 THWN aluminum conductors at an ambient temperature of 38°C?

• A. 40 Amps
• B. 44 Amps
• C. 48 Amps
• D. 50 Amps

Answer: (B)

The current-carrying capacity, or ampacity, of conductors is influenced by several factors, including the size of the conductor, the type of material, and the ambient temperature. For No. 6 THWN aluminum conductors, the standard ampacity rating is typically found in the National Electrical Code (NEC) tables, which provide base ampacity ratings at 30°C (86°F).

When considering ambient temperature, adjustments must be made according to temperature correction factors as outlined in the NEC. At an ambient temperature of 38°C (approximately 100°F), the ampacity of the conductor must be adjusted downward from its standard rating to reflect the increased heat that contributes to potential overheating of the wire.

For No. 6 THWN aluminum conductors, the base ampacity rating in optimal conditions would generally be around 55 Amps. However, applying the appropriate adjustment factor for the higher temperature of 38°C results in a current-carrying capacity of approximately 44 Amps.

Therefore, the selection of 44 Amps is based on these factors and aligns with the NEC guidelines for aluminum conductors, confirming that this is the correct choice in determining the suitable ampacity at the given temperature.