Vd (Volts) = (Length x Current x 0.017) / Cross Sectional Area (mm²)
Ignoring voltage drop doesn’t just make your lights dim; it burns out motors, voids warranties, and fails compliance under .
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]. voltage drop calculator australia
| 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 |
In Australia, we deal with unique challenges. Our properties are massive (often measured in hectares, not square meters), and our standard 230V single-phase power has a long way to travel. Vd (Volts) = (Length x Current x 0
Avoid voltage drop penalties and fire hazards. A guide to the Australian Wiring Rules (AS/NZS 3000) and the easiest way to calculate cable sizes for long runs. If you are wiring a shed in rural Queensland, running lights in a Sydney high-rise, or installing a solar farm in the outback, you face the same silent enemy: Voltage Drop .
Next time a customer asks, "Why can't I just use 1.5mm² cable for my 200-meter driveway light?" send them here. The Best Tool for the Job Instead of
But who wants to do math in a trench or on a roof? Use a calculator. If you don't have a calculator handy, memorize these "Rough as guts" rules for Copper V-90HT (Standard building wire):