A power supply arrangement for a suction device is provided, which is optionally operable using direct current or alternating current, including a first connection connectible to a direct current source, a second connection connectible to an alternating current source, a third connection connectible to a consuming unit of the suction device, an electrically isolated converter connected on the input side to the first connection, and a switchover device connected to an output of the converter, the second connection and to the consuming unit, wherein the switchover device allows selection of whether the consuming unit is actively connected to the converter or the second connection for power supply, and wherein the switchover device has one or more components each with an electrical safety clearance that is at least 4 mm in respect of the creepage distance and the total of the creepage distances of the components is at least 8 mm.