An electrical system includes a first conduction terminal, a second conduction terminal, N power units and N supporting devices. The N power units are electrically connected between the first conduction terminal and the second conduction terminal in series, and N is an integer greater than or equal to 2. Each of the N supporting devices includes a conductive part and a support part. Each of the N power units is disposed on the corresponding conductive part. The conductive part is electrically connected with a power terminal of one of the N power units or electrically connected with a reference potential of the electrical system. The support part is connected between the corresponding conductive part and a ground potential.