Assembly for an uninterrupted power supply

The arrangement has network (AC3) to be protected or load to be protected connected to inverter output of inverter (3). The rectifier input or second supply grid (AC2) is connected with inverter output via switching unit (4). The rectifier (1), inverter and switching unit are controlled by controller having first control part (5) and second control part (6). A CAN bus (8,9) supplies auxiliary current. Each CAN bus is connected with input to supply auxiliary current to first and second control part, respectively so that control parts are supplied with electricity.