AWG Wire Size Calculator

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Inputs
Result
8 AWG

8 AWG is the smallest listed conductor that passes 20.0 A required ampacity and 3.00% voltage-drop limit.

Required ampacity20.0 A
Selected ampacity40.0 A
Voltage drop2.61 V / 2.18%
Derating applied100%
Next checks
  • Use the selected size as a planning reference, then verify insulation, terminals, installation method, ambient correction, and local code.
  • Run breaker, conduit fill, and voltage-drop checks together before finalizing.
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