A 220 volt 50 amp plug is for rvs and really large power hungry appliances such as ranges and furnaces.
Before you wire a 240 volt plug look at its current rating which is marked clearly on it. Wiring a 30 amp 240 volt outlet.
20 Amp Generator Plug Wiring Diagram Wiring Diagram
30a Dryer Plug Wiring Diagram Wiring Diagram All
2pdt Switch Wiring Diagram Data Pre