Determine the maximum current-carrying capacity for each conductor when four 1/0 AWG THW current-carrying copper conductors are installed in a common raceway with an ambient temperature of 86 degrees F.

To determine the maximum current-carrying capacity for four 1/0 AWG THW copper conductors installed in a common raceway, we need to consider several factors, including the ampacity table for copper conductors and the conditions of installation, such as the ambient temperature.

For 1/0 AWG copper conductors, the base ampacity at 86°F (30°C) is typically around 130 amperes per conductor when installed in a raceway without any derating factors. However, because four conductors are grouped together in a common raceway, derating factors must be applied according to the NEC (National Electrical Code).

According to NEC guidelines, when more than three conductors are installed together, the ampacity must be reduced to account for the additional heat generated by the bundling of conductors. With four conductors, typically a derating factor of 80% is applied.

Calculating the derated capacity:

1. The base capacity of one 1/0 AWG is 130 amperes.

2. Applying the derating factor of 80% results in:

130 amperes x 0.8 = 104 amperes.

However, 104 amperes would not