Electrical system including: - a first positive input terminal and a first negative input terminal intended to be connected respectively to a positive terminal and a negative terminal of a first electric power source which has a first voltage (V 1) between its positive terminal and its negative terminal, - a second positive input terminal and a second negative input terminal intended to be connected respectively to a positive terminal and a negative terminal of a second electric power source which has a second voltage (V 2) between its positive terminal and its negative terminal, the second supply voltage (V 2) being greater than the first voltage (V 1), - an electrical device connected, on one hand, to the first input terminals (124, 126) and, on the other hand, to the second input terminals (128, 130), the electrical device having an electric conduction path between the second positive input terminal and the first negative input terminal, - a first switch via which the electrical device is connected to the second positive input terminal, - a detection device configured to: - detect whether a voltage between the second positive input terminal and the second negative input terminal is less than or equal to a predefined threshold, - in the case of such a detection, order the first switch to open, characterized in that it furthermore comprises: - a second switch via which the electrical device is connected to the second negative input terminal, and wherein the detection device is furthermore configured to order the second switch to open in case of detection that the voltage between the second positive input terminal and the second negative input terminal is less than or equal to the predefined threshold. - a first positive input terminal and a first negative input terminal intended to be connected respectively to a positive terminal and a negative terminal of a first electric power source which has a first voltage (V 1) between its positive terminal and its negative terminal, - a second positive input terminal and a second negative input terminal intended to be connected respectively to a positive terminal and a negative terminal of a second electric power source which has a second voltage (V 2) between its positive terminal and its negative terminal, the second supply voltage (V 2) being greater than the first voltage (V 1), - an electrical device connected, on one hand, to the first input terminals (124, 126) and, on the other hand, to the second input terminals (128, 130), the electrical device having an electric conduction path between the second positive input terminal and the first negative input terminal, - a first switch via which the electrical device is connected to the second positive input terminal, - a detection device configured to: - detect whether a voltage between the second positive input terminal and the second negative input terminal is less than or equal to a predefined threshold, - in the case of such a detection, order the first switch to open, - detect whether a voltage between the second positive input terminal and the second negative input terminal is less than or equal to a predefined threshold, - in the case of such a detection, order the first switch to open, - a second switch via which the electrical device is connected to the second negative input terminal, and wherein the detection device is furthermore configured to order the second switch to open in case of detection that the voltage between the second positive input terminal and the second negative input terminal is less than or equal to the predefined threshold.