You can, but with strict requirements. Most problems stem from using the wrong cord.
Requirements:
- The plug and socket of the extension cord must be of watertight construction.
- The cord must be in perfect condition. Inspect it for any damage or wear.
- It must be heavy-duty and rated for the amperage of the pressure washer (14.5A). An undersized cord will cause voltage drops, overheating, and tripping.
Procedure: If the unit trips or won't start with your extension cord, unplug it. Try the pressure washer plugged directly into a grounded wall outlet. If it works, your extension cord is defective or inadequate.
Even with a proper cord, ensure you are not overloading the circuit. Switch off other high-draw appliances on the same circuit. Short voltage drops when starting can influence other equipment (like causing lights to blink). If problems persist, contact your local power supply authority for information on your mains impedance.
Never carry the machine by the cord or yank the cord to disconnect it. Keep the cord away from heat, oil, sharp edges, and the spray path.