Does sun light affect the Cable rating ?

It is a practice to cover the cable trays, in case of direct exposure to sun rays.More than the temperature, it is the ultraviolet rays in the sun rays which can adversely affect the cable insulation by breaking up the bonds in the chemical chain, on prolonged exposure. Generally, cables with black outer sheath are expected to be ultraviolet resistant.

Yes the  Sun Light affect the cable current carrying capacity.

yes sun light affect the cable rating . when cables directly exposed to sun light which include ultravilote rays. the cables are derating due to temperature and  ultravilot rays. the ultraviolet rays in the sun light adversely influance the cable insulation by breaking up the bonds in the chemical chain which decrease the voltage rating of the cables . so its practice to cover the cable trays.

YES answer in a simple way