What electrical requirements does the WFW9300VU need, and can I use an extension cord?

The washer requires a 120 volt, 60 Hz, AC only, 15- or 20-amp fused electrical supply, and must be plugged into a grounded 3-prong outlet within 6 ft (1.8 m) of the power cord connection point on the back of the washer. Do not use an extension cord, do not remove the ground prong, and do not use an adapter — failure to follow these instructions can result in death, fire, or electrical shock. A time-delay fuse or circuit breaker and a dedicated circuit are recommended. (Pages 7, 5)