Which scenario would NOT require the application of T. 310.15(C)(1)?

The scenario that would not require the application of T. 310.15(C)(1) is related to a conduit containing only one conductor. The T. 310.15(C)(1) applies when calculating the allowable ampacity for conductors in raceways or cables, taking into consideration the number of conductors and the derating factors associated with that.

When a raceway has multiple conductors, they generate heat as they carry current, and the derating factors from T. 310.15(C)(1) come into play to ensure that the conductors do not exceed their maximum temperature ratings. The more conductors present, the more significant the heating issue becomes, which is addressed by applying the derating factors outlined in the code.

For conduits or raceways containing a single conductor, there is no risk of heat buildup from the interaction with other conductors, so the considerations of T. 310.15(C)(1) do not apply. Therefore, if a raceway only has one conductor, there are no other conductors to affect its ampacity, and it can be rated at its full capacity without any derating. This makes the scenario with the single conductor a clear case where T. 310.15