For a group of thirty-two 12 AWG THHN copper conductors installed at 45°C, what is the final ampacity of each conductor?

To determine the final ampacity of 12 AWG THHN copper conductors installed at 45°C, we start with the standard ampacity values for 12 AWG copper conductors, which typically follow the National Electrical Code (NEC) guidelines.

At a standard temperature of 30°C, the ampacity for a 12 AWG THHN copper conductor is generally around 20 Amperes. However, as the temperature increases, the ampacity of the conductor decreases due to the properties of the materials used. Copper's resistance increases with temperature, affecting how much current it can safely carry without overheating.

To find the adjustment factor for the temperature of 45°C, we need to reference a correction factor chart. The NEC provides correction factors to adjust the ampacity values based on temperature. For conductors operating above 30°C, an adjustment must be applied. In this case, the correction factor for 45°C typically reduces the ampacity significantly.

Using the standard ampacity of approximately 20 Amperes for 12 AWG at 30°C, the adjustment for 45°C results in an ampacity of about 10.44 Amperes. This adjustment accounts for the higher temperature which reduces the conductor's ability