Modular lighting system

The lighting system has fixed network connection unit (3) and mobile lighting unit (2) provided with identical electrical plug-in contacts (5), for electrically connecting mobile lighting unit with network connection unit. The network connection unit has electrical connectors (6) for connection of network connecting unit to electrical supply network. The electrical connectors are formed as electrically connecting terminals (7), such that the network connection unit has a rail holder for arrangement on mounting rail of electrical distribution system.