Science & Engineering

DC Wire Gauge (AWG) Selector

Picks the right AWG gauge for a DC circuit from the current, voltage, run length, and allowed voltage drop. It works for copper or aluminum and reports the gauge, ampacity, and actual drop.

How to use
  1. Enter the circuit current and system voltage.
  2. Enter the one-way cable length and the allowed voltage drop.
  3. Choose copper or aluminum.
For study and estimation. Verify against authoritative data before relying on a result.
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Common questions

Why does cable length affect wire size?

A longer run has more resistance, which raises the voltage drop, so longer circuits need a thicker wire to stay within the limit.

Is copper or aluminum better for a given gauge?

Copper carries more current and drops less voltage for the same gauge, so aluminum runs usually need to step up a size or two.

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