Termination Temperature Ampacity Limit (NEC 110.14(C))
The NEC 110.14(C) termination rule wire-ampacity leaves out: the usable ampacity is the LESSER of the lowest-rated termination column (60 or 75 C) and the derated 90 C value. The 90 C column is for the ambient/fill derating math only -- it never reaches the terminals. Circuits <= 100 A default to 60 C unless listed 75 C; over 100 A use 75 C.
Formula and source
termination_ampacity = over_100a ? amp_75c : (termination_rating == 75 ? amp_75c : amp_60c); derated_90c = amp_90c x derate_factor; governing = min(termination_ampacity, derated_90c).
NEC 2023 (NFPA 70). 110.14(C) (temperature limitations of terminations) with Table 310.16.
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