A temporary voltage supply for a consumer includes a switching device with an auxiliary power supply; a control device supplied by the auxiliary power supply if an operating power supply fails; and a switching device which is activated by the control device and actuates the consumer via auxiliary power from the auxiliary power supply. The auxiliary power supply is configured in such a manner that, upon request, by actuation of a switch, the control device is provided with a sufficient amount of power for a final operating sequence after the operating power supply fails.