Electrical installation or device equipped with a power supply unit comprising a voltage converter having primary and secondary parts respectively defining a primary side and a secondary side of this electrical installation or device, this power supply unit also comprising on said primary side: - an input circuit including a main rectifier; - a control circuit of the primary part of the converter which controls the electrical energy flowing in the primary power path of this primary part with a high voltage; - receiving means of at least an external control signal which provides at its output, in response to this external control signal, a wake-up signal for waking up the electrical installation or device from a very low power mode ("Power-down" mode) or generating means of such a wake-up signal; - a power supply controller arranged for receiving said wake-up signal and for providing to said control circuit at least a first control signal for switching OFF the electrical energy in said primary power path when the electrical installation or device enters said very low power mode, so that the secondary part of the converter is not supplied anymore, and for switching ON the electrical energy in said primary power path when it receives from said receiving means or generating means said wake-up signal; - primary supply voltages generation means arranged for supplying said control circuit, said receiving means or generating means and said power supply controller; characterized in that said primary supply voltages generation means comprises a first voltage reducer (Figure 5) or a voltage reducer unit with a first output, supplying in parallel the control circuit and a part of the power supply unit comprising the receiving means or generating means and the power supply controller, and in that this first voltage reducer or voltage reducer unit is arranged for receiving an AC signal from an electrical supply source supplying the electrical installation or device and is formed by a capacitive divider, this first voltage reducer or voltage reducer unit being associated to a dedicated rectifier which charges an intermediate voltage capacitor for supplying in parallel said control circuit and said part of the power supply unit. - an input circuit including a main rectifier; - a control circuit of the primary part of the converter which controls the electrical energy flowing in the primary power path of this primary part with a high voltage; - receiving means of at least an external control signal which provides at its output, in response to this external control signal, a wake-up signal for waking up the electrical installation or device from a very low power mode ("Power-down" mode) or generating means of such a wake-up signal; - a power supply controller arranged for receiving said wake-up signal and for providing to said control circuit at least a first control signal for switching OFF the electrical energy in said primary power path when the electrical installation or device enters said very low power mode, so that the secondary part of the converter is not supplied anymore, and for switching ON the electrical energy in said primary power path when it receives from said receiving means or generating means said wake-up signal; - primary supply voltages generation means arranged for supplying said control circuit, said receiving means or generating means and said power supply controller;