. Ballasts are needed for discharge lamps to connect the lamp to the mains. Lamps, ballasts and starters are mounted in the luminaire with the wiring and lamp bases, reflectors distribute and redirect the light emitted from the lamp and louvers shield the user from glare. Control systems interact with the building where they are installed. This means that the spider net of interactions and impacts is related with the architecture of the building (shape, space orientation etc