An electronic control unit receives power from multiple supplies and distributes the power to loads. The electronic control unit has power terminals for the supplies, load terminals for the loads, and wiring with a main line between a first and second power terminal. Branch lines connect the main line to each load terminal. Disconnect circuits are installed on the main line and on each branch line, and can be switched between conducting (connected) and non-conducting (disconnected) states by a controller. The disconnect circuits include a main-line disconnect circuit, load disconnect circuits on the branch lines, and first and second power disconnect circuits on respective main-line sections. When the controller in the electronic control unit detects an abnormal condition based on current and/or voltage, the controller disconnects the main line and at least one terminal circuit to cut off power.