Voltage Drop Calculator Australia _verified_ May 2026

On a 415V 3-phase motor, you calculate voltage drop for one conductor, but the total loss affects the motor's torque. Always use a calculator with a "3-phase" toggle. The Best Tool for the Job Instead of breaking out the slide rule, use our Australian Voltage Drop Calculator [Link to your tool].

| Cable Size (mm²) | Max run for 10A (230V) @ 5% | Max run for 20A (230V) @ 5% | | :--- | :--- | :--- | | | 35 meters | Not recommended | | 2.5mm² | 58 meters | 29 meters | | 4mm² | 93 meters | 46 meters | | 6mm² | 140 meters | 70 meters | voltage drop calculator australia

Vd (Volts) = (Length x Current x 0.017) / Cross Sectional Area (mm²) On a 415V 3-phase motor, you calculate voltage

Pro Tip: If your run is over 100 meters, (e.g., from 2.5mm² to 6mm²) rather than one. 3 Critical Mistakes Aussies Make 1. Forgetting the Return Path When using a calculator, do you double the distance? Yes. The current travels down the active AND back the neutral. If your shed is 50m from the switchboard, the total circuit length is 100m . Most good calculators ask for "One-way distance" and do this math for you. | Cable Size (mm²) | Max run for