I agree with Jwhite wholeheartedly. The installation of the dedicated receptacle should have been done in a matter so that an extension cord would not be required. The intent of the NEC is to create an installation whose safety does not rely on the general public understanding what wire guage is and how under-sized extension cords can lead to excessive voltage drop (with damage to equipment, esp. rotating loads) or excessive heating due to undersized cord wiring (and therein possible fire hazards).According to NFPA you should not ever use an extension cord in a permant or semi perminant manner. You should extend the circuit to within reach of the appliance's factory installed cord.