Which of the following installations does NOT require the application of Table 310.15(C)(1)?

In the context of electrical installations, Table 310.15(C)(1) is used to determine the allowable ampacity of conductors based on various conditions such as the number of conductors, temperature ratings, and their installation methods.

The option referring to a metal wireway containing ungrounded conductors does not require the application of Table 310.15(C)(1) because metal wireways are considered a raceway type installation. The conductors housed within a metal wireway are protected and typically have a specific and known heat dissipation characteristic. Since their installation conditions mitigate the effects that Table 310.15(C)(1) accounts for, there’s no need to apply the table to determine the ampacity of conductors within such a system.

In contrast, installations such as conduits with parallel conductors, control circuit conductors, and bundled nonmetallic cables each have unique characteristics that affect their thermal performance and thus require the use of the table to ensure safe operation and compliance with the National Electrical Code (NEC). These conditions affect how the conductors dissipate heat and can lead to potential risks if not properly accounted for, necessitating the use of Table 310.15(C)(1) for those specific cases.