Electrical Cable Size Chart Amps Australia Patched May 2026
Example: 20A over 50m using 4mm². (50 x 20 x 0.017) / 4 = 4.25 Volts lost. (Acceptable, under 7.2V). Don't search the chart. Ask yourself these 3 questions:
That chart lies if the cable is long. This is where 90% of DIY fails happen. Part 2: The "Voltage Drop" Monster (Distance kills amps) Imagine water flowing through a hose. A short hose (10m) gives full pressure. A long hose (100m) dribbles out. electrical cable size chart amps australia
Over distance, voltage drops. When voltage drops, amps spike, wires melt, motors die. The 3% Rule (Australia) For power & light circuits, your voltage drop cannot exceed 3% of 240V (which is 7.2 Volts lost). Example: 20A over 50m using 4mm²
| Cable Size (mm²) | Max Amps (In free air/Clipsal) | Max Amps (In wall/Conduit) | Typical Use Case | | :--- | :--- | :--- | :--- | | | 11A | 10A | 1mm is dead. Use 1.5mm for lights. | | 1.5 mm² | 16A | 14A | Lighting circuits (LEDs are fine, halogens need this). | | 2.5 mm² | 27A | 22A | Standard Power Points (10A GPOs). Your house walls. | | 4.0 mm² | 37A | 30A | Ovens, cooktops, air conditioners (up to 25A). | | 6.0 mm² | 48A | 38A | Large ovens, instant HWS, Sub-mains (shed feed). | | 10 mm² | 67A | 52A | Small switchboards, EV chargers (7kW). | | 16 mm² | 88A | 69A | Big sheds, induction cooktops. | Don't search the chart