What is the allowable ampacity of each conductor when 4 current-carrying 10 AWG, THW copper conductors are installed in a raceway?

To determine the allowable ampacity for each of the four current-carrying 10 AWG THW copper conductors installed in a raceway, it is essential to refer to the National Electrical Code (NEC) tables. According to the NEC, the base ampacity for 10 AWG copper conductors is 30 amps. However, when multiple conductors are installed together in a raceway, adjustments must be made based on the number of conductors to account for heat buildup.

For four conductors, the NEC applies a derating factor from the adjustment tables. Specifically, with more than three conductors, the allowable ampacity is reduced to 80% of the base ampacity. Calculating 80% of the 30 amps base ampacity results in 24 amps per conductor.

This would normally indicate that the allowable ampacity for each conductor is 24 amps. However, 4 conductors in raceway would more accurately allow for 4 conductors (30 amps base) to be reduced to an appropriate capacity, which results in further examination of the installation settings and whether additional adjustment factors should apply. Given the other factors or installations can lead to scenarios where the final numbers might differ, it stands accurate within the most