The invention relates to illumination, especially to a grid for illumination apparatus. This invention provides a grid (100) for attenuating electromagnetic radiation from a light source. The grid comprises a plurality of baffles (110), each baffle being electro conductive, wherein the plurality of baffles are configured to form a plurality of cells (120), each cell being formed as a waveguide so as to attenuate the electromagnetic radiation from the light source. In this way, the electromagnetic radiation from the light source can be reduced or prevented so as to decrease the danger to users.