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Wire Ampacity Calculator (NEC 310.16)
Look up the allowable ampacity of copper or aluminum conductors by size and insulation temperature rating, per NEC Table 310.16.
How it works
NEC Table 310.16 allowable ampacity by conductor size, material, and insulation temperature rating.
Worked example
8 AWG copper at the 75 C column = 50 A.
When to use it
- NEC 2023 values, based on 30 C ambient and no more than three current-carrying conductors.
- Terminations usually limit you to the 75 C column per NEC 110.14(C).
- Apply ambient and bundling correction factors for real installations, and verify with the AHJ.
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All results are an engineering estimate — not for custody transfer. Field measurement and certified tables govern.