Appliance receptacles, rated from 15 to 50 amps, 240 volts and from 20 to 50 amps, 120/240 bolts, each require a special plug that will fit only that receptacle. Take care when replacing appliance receptacles because they have two hot wires, usually red and black, going to them. They may or may not have a separate grounding wire.
CAUTION: before beginning any work, turn off the power to the circuit. For a 240-volt circuit, you may have to remove two fuses or trip a two-handed circuit breaker.