Cable Ampacity Calculator — Free Online Calculator
Find the maximum current rating (ampacity) for any wire gauge at different temperature ratings per NEC Table 310.16.
How to Use This Calculator
Select wire gauge, material, insulation temperature rating, and ambient temperature. The calculator returns the base ampacity from NEC Table 310.16 and applies temperature correction factors.
The Formula Explained
Ampacity values come from NEC Table 310.16, which lists maximum current for each conductor size based on insulation temperature rating and conductor material. When ambient temperature exceeds 30°C, correction factors from NEC Table 310.15(B)(1) reduce the allowable ampacity.