Why some pressure washers need certain Extension Cables

DID YOU KNOW

Using a undersized extension cable can cause issues.

Using a 1mm² or 1.25mm² core extension cable with a pressure washer is generally not recommended and can be hazardous.

Pressure washers are high-power devices that draw significant current, and undersized cables (thin wires) cause substantial voltage drop over distance, leading to poor performance, overheating, and potential damage to the machine. 

 

• Reduced Performance: As the voltage drops due to resistance in the thin, small-diameter cable, the pressure washer motor cannot pull enough power. This results in reduced pressure, "pulsing" water pressure, or the motor failing to start properly.
• Motor Damage: Running an electric motor on low voltage causes it to draw more current to compensate, leading to overheating and significantly shortening the life of the machine. 

• Hot Cable/Plug: The high current draw, combined with high resistance from the thin 1mm/1.25mm wire, causes the extension cable and plug to get very warm or hot.
• Melting Hazards: In extreme cases, this heat can melt the plug, socket, or the cable insulation, creating a serious fire hazard.
• Tripping Breakers: The increased current draw is likely to trip the circuit breaker in your home or on the extension cable itself. 

• 1.25mm² Limit: Flexible, 1.25mm² cables should not generally exceed 12 meters (approx. 40 ft) in length when used for high-power tools.
• 1mm² Limit: 1mm² cable is even more restricted and generally unsuitable for anything beyond very short, low-load use.

 

• Use 1.5mm² or 2.5mm²: For a pressure washer, use a heavy-duty cable with a conductor size of at least 1.5mm² (for shorter distances) or 2.5mm² (for longer distances, up to 25m).
• Use Shortest Cord Possible: Keep the extension lead as short as possible to minimize voltage drop.
• Use RCD Protection: Ensure the extension lead is plugged into an RCD (Residual Current Device) protected socket.
• Alternative: It is often better to use a longer high-pressure water hose and keep the electrical cord short.