Lighting system and cap for such lighting system

A lighting system comprising an electrical lamp (6) having an electrical lamp connector (32), a holder (5) having a front electrical connector adapted to be back-connected to a power supply and a cap (7) to interface the electrical lamp and the holder, said cap extending along a mounting direction between a top side for receiving the lamp connector and an opposite bottom side for receiving the holder connector, and having axial holes extending between the bottom side and the top side for receiving within at least a part of an electrical cap connector able to electrically connect the lamp connector with the holder connector once the lighting assembly is assembled. The cap further comprises a cap guide and the holder further comprises a holder guide, said cap guide and holder guide being adapted to cooperate with one another by fitting in the mounting direction, such that any significant motion of the cap into directions perpendicular to the mounting direction is prevented by the holder guide, ensuring a positi