To reduce glare
Standard Downlights give the light which integrates an open reflector and / or shielding device, usually recessed, whose light spread forms a cone shape and directly downward, recommended for use in horizontal planes.
Wallwasher downlightings are mostly recommended for the combination of lighting walls and floors. These lights with asymmetical reflectors provided, when properly positioned, an optimum light distribution covering different points of wall and floor.
In case of non-uniform illuminance occur, several problem will come out:
Luminaire in which protection against electric shock does not only rely on the basic insulation, but also on the additional safety insulation that are provided for the connection for the accessible conductive parts to the protective conductor in the fixed wiring of installation that the obtainable conductive parts cannot become live in case of a failure of the basic insulation.
A luminaire in which protection against electric shock does not only rely on the basic insulation, but also on the additional safety insulation, such as double insulation or reinforced insulation, being no provision for protective earthing or reliance upon installation condition.
Aluminaire in which protection against electric shock is based on the safety extra low voltages (SELV) or in which voltages higher than SELV are not generated. The SELV is defined as a voltage which does not exceed 50V r.m.s. at alternative current between conductors or conductor and earth in a circuit. A class III luminaire must never be provided with earthing.