What is the ampacity of a single 8 AWG THWN-2 copper conductor installed in free air at 30°C?

To determine the correct ampacity of a single 8 AWG THWN-2 copper conductor installed in free air at a temperature of 30°C, we can refer to the National Electrical Code (NEC) ampacity tables. For THWN-2 conductors, the ampacity is influenced by factors such as the type of insulation and the temperature rating.

At 30°C, a single 8 AWG copper conductor has an ampacity of 80 amps according to Table 8 in the NEC, which outlines the ampacity for conductors based on various factors including installation conditions. The "in free air" installation allows for more efficient heat dissipation compared to conductors that are bundled or in conduit, further supporting this higher ampacity.

In summary, the correct answer, indicating an ampacity of 80 amps for the specified conditions, is supported by the established code tables and temperature ratings for these specific conductors.