Formula variables
- Material selects copper or aluminum resistivity and coefficient.
- Area is conductor cross-sectional area in mm2.
- Length is one conductor path length in metres.
- Temperature factor adjusts resistance from the 20 C base.
Assumptions
- Resistance is calculated from material resistivity, conductor area, length, and temperature factor.
- The base resistivity values match the site voltage-drop and resistance calculators.
- Temperature correction uses rounded material coefficients from a 20 C base.
- This calculator does not replace ampacity review, insulation temperature limits, terminal ratings, or manufacturer data.
Examples
Copper resistance. 16 mm2 copper over 100 m at 20 C estimates about 0.1078 ohm.
Temperature workflow. Higher conductor temperature raises resistance and can change a voltage-drop estimate.