Lamp unit for fluorescent tubes has a housing open at the top carrying the tube holders and the starter equipment which is attached to a support rail covering the open side of the housing. The support rail includes conductors extending over the whole of its length fitted if necessary with earth or other protective leads which have a connection to the contacts of the lamp switch located in the tube holder. The contacts having a conducting connection to each other and located inside a switch may be selectively switched on to the phase leads which are formed as flat band cables open on one side.
