Using an extension cord with a microwave is generally not recommended. Microwave ovens draw a considerable amount of electrical power, and using an extension cord can create potential safety hazards.
The primary concern with using an extension cord for a microwave is that it may not be able to handle the high power load required by the appliance. Microwave ovens typically require a dedicated circuit to deliver enough power safely. If the extension cord is not rated for the wattage and amperage needed by the microwave, it could overheat and potentially cause a fire.
If you find that your microwave's power cord is not long enough to reach the electrical outlet, it's better to use a different outlet or consider having a new outlet installed closer to the microwave's location by a qualified electrician. This ensures that the microwave is connected to a proper and safe power source without the need for an extension cord.
In general, it's best to follow the manufacturer's instructions and guidelines provided in the microwave's user manual regarding power requirements and electrical connections. This helps ensure the safe and efficient operation of the appliance.