Abstract: A modular lighting system includes a mobile lighting unit and a stationary power supply network connection unit, wherein the lighting unit has at least one light source, wherein the lighting unit and the network connection unit have corresponding electrical contacts for electrical connection of the lighting unit to the network connection unit, wherein the network connection unit has electrical connections to connect the network connection unit to an electrical power supply network, wherein the electrical connections are formed as electrical connection terminals, and wherein the network connection unit has a rail mount for installation on a mounting rail of an electrical distribution system.