Claimed by the inventions is a cable tray (23, 140) comprising a first part (51) constituting one piece having a uniform thickness, the first part (51) forming at least a first support surface (52) of a first accommodation (53) for the plurality of cables (54), the first part (51) having a plurality of first through holes (15) formed by a first plurality of edges (19) in the first part (51), wherein at least a part of each said edge (19) protrudes and is directed with an angle away from the support surface (52) of the first accommodation (53), where 45°