What is the allowable ampacity of each conductor when 8 current-carrying 8 AWG, THW copper conductors are installed in a raceway at an ambient temperature of 45 degrees Celsius?

To determine the allowable ampacity of conductors, it's crucial to reference the National Electrical Code (NEC) tables, specifically Table 310.16, which outlines ampacity based on conductor size, number of conductors, and ambient temperature.

For 8 AWG THW (thermoplastic heat and water-resistant) copper conductors, the base ampacity at 30 degrees Celsius is typically around 50 amps. However, since the installation environment has an ambient temperature of 45 degrees Celsius, adjustments need to be made according to NEC guidelines.

When there are multiple current-carrying conductors in a raceway, the ampacity must be derated. For eight current-carrying conductors, the derating factor from NEC Table 310.15(B)(3)(a) is 60%. Therefore, the calculation is as follows:

1. Start with the base ampacity of 50 amps.

2. Apply the derating factor of 60%, which results in:

50 amps x 0.60 = 30 amps.

Finally, because the ampacity must also be adjusted further for the elevated ambient temperature of 45 degrees Celsius using the corrections factors in the NEC, the final allowable ampacity recalcul