Voltage Drop Calculator

Calculate the voltage drop in your electrical circuit to ensure proper wire sizing and safe operation.

Distance from panel to load (not round trip)

Common Wire Sizes Used

Most frequently calculated wire sizes

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Calculation Statistics

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Voltage Drop Guides & Articles

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How Voltage Drop Works

  • What is Voltage Drop: The decrease in voltage as current flows through wire resistance
  • NEC Recommendation: Maximum 3% drop for branch circuits, 5% total for feeder + branch
  • Copper vs Aluminum: Copper has lower resistance but costs more than aluminum
  • Wire Size: Larger gauge numbers mean smaller wire with more resistance
  • Distance Matters: Longer runs require larger wire sizes to maintain acceptable voltage

Frequently Asked Questions

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