A system for switching between first and second voltage supply units, the system may include a first interface unit that is connected between a first voltage supply unit and an output unit, a second interface unit that is connected between a second voltage supply unit and the output unit; a controller that is arranged to select a selected voltage supply unit and to instruct the first and second interface units and the output unit to facilitate a provision of a selected supply voltage provided from the selected voltage supply unit to a load coupled to the output unit. Each interface unit may include a positive input port, a negative input port, a positive output port and a negative output port. The negative and positive output ports of the first interface unit are isolated from the negative and positive output ports of the second interface unit, respectively.