A power supply unit, an electrically operated system and a method for operating an electrical system, wherein the power supply unit connects through a basic supply voltage or a buffer voltage, which is provided by an energy store unit, where to perform a controlled switch-on process of the electrical loads, a switch-on delay time is specified, after the expiration of which the basic supply voltage or the buffer voltage is connected through at the output of the power supply unit, and where to perform a controlled switch-on process of the electrical loads, a voltage is output only when a charge level of the energy store unit is greater than or equal to a threshold value of the energy store charge level such that switch-on management for power supplies that ensures absolutely safe interruption-free and thus trouble-free start-up of a plurality of electrical loads is achieved.