Table

Copper vs Aluminum Conductor Properties

Copper vs Aluminum Conductor Properties reference with assumptions and boundary notes.

Reference boundary

Material-property comparison only. This table does not approve one conductor material as a substitute for another.

Reference table

Compare copper and aluminum material properties used in resistance and voltage-drop estimates.

Formula/property basis uses common engineering material constants rounded for reference use.
PropertyCopperAluminumReference use
Resistivity at 20 C0.017241 ohm mm2/m0.028264 ohm mm2/mResistance and voltage-drop estimates
Conductivity relationshipBaselineAbout 61 percent of copperExplains larger aluminum sizes for equal resistance
DensityAbout 8.96 g/cm3About 2.70 g/cm3Weight comparisons, not ampacity
Temperature coefficient0.00393 per C0.00403 per CResistance temperature adjustment
Use notes
  • Use this table for preliminary reference and arithmetic checks only.
  • Confirm equipment ratings, product markings, installation conditions, utility requirements, and the local authority requirements before design or field use.