A direct current power supply for a washing appliance powered is disclosed. The power supply includes a switch mode power supply which supplies direct current at a low voltage level from a high direct voltage supply and a pair of commutation devices as a buck converter, an active switching device connected across the input of one of the commutation devices, a latching circuit which controls the active switching device to cause the commutation device to switch off to disable the buck converter, and a push button switch for disabling the latching circuit to cause the active switching device to switch off to allow the one commutation switch to function and thereby enable the buck converter.