Toggle water heater between 120 and 240 volt: http://waterheatertimer.org/How-to-wire-water-heater-f… | Wire switch, Home electrical wiring, Basic electrical wiring
Control 240 volt using switch
Control 240 volt using switch
Is this smart light switch wiring compatible in Australia? (it does support 240v) : r/perth
How to Wire Double Pole, Single Throw Switch? Wiring DPST