You need to power a 5kW (5000W) heater at 230V over a distance of 30 meters. Calculate Current: Determine Allowable Voltage Drop (5%): Calculate : Consult Chart: Look at a standard copper cable table. A 2.5mm22.5 m m squared cable typically has a drop of (too high), whereas a 4mm24 m m squared cable has a drop of roughly Final Choice: Use 4mm24 m m squared copper cable. Summary Checklist Load Power: Know your total wattage.
: Power factor (usually 0.8 for motors, 1.0 for resistive loads). 2. The Voltage Drop Formula how to calculate cable size in sq mm formula
Permissible mV/A/m=Allowable Voltage Drop×1000I×LPermissible m cap V / cap A / m equals the fraction with numerator Allowable Voltage Drop cross 1000 and denominator cap I cross cap L end-fraction Length of the cable in meters. I: Design current in Amps. You need to power a 5kW (5000W) heater
For a three-phase circuit: