The invention relates to a circuit assembly for operating at least one lighting means, comprising at least one master device; at least one slave device; and a bus system having at least one bus, by means of which bus system the at least one master device and the at least one slave device are coupled; wherein the bus is designed as a two-wire cable, wherein the at least one master device has at least one feeding connection, which is coupled to the bus and is designed to place a control signal on the bus, wherein the at least one master device is coupled to a first voltage supply; wherein the at least one slave device comprises a non-feeding connection, which is coupled to the bus, wherein the slave device comprises a connection for at least one lighting means, a second voltage supply, and a read-out device for reading out the control signal on the bus, wherein the read-out device comprises a potential-isolating device and wherein the connection for the at least one lighting means and the second voltage supply are provided on the side of the read-out device isolated from the bus with regard to potential.