If the SY is not 100% shielded from the sun then you should look towards another cable with UV protection attributes ..the outer sheath is so designed on purpose mainly for machine use and similar control needs as it is see through and any degradation of the shielding/braid can be easily inspected.
Because the sheath is clear it lacks a lot of attributes found in most cable sheaths and even the ones it gives like moderate acid and oil resistance only apply at room temp' and can't be guaranteed when subject it to temp extremes... How its use has been catapulted into this fits all solution when it is clearly unsuitable for most purposes the average Joe spark utilises it for...
Pop onto RS Components web site and you'll find many better suited to your needs that don't have the limitations SY does although RS's downfall is it doesn't cut to length so Scatts maybe a better option .. the problem is most general wholesalers don't stock any other shielded cables so i assume this is a reason for its explosion into the scene of misuse as SY was promoted as a suits all cable with added mechanical protection ...a lot of uses took this as a open door for blindly misusing it.
The problem with screened cable is the expense of suitable glands but as SY has flooded the market it has seen a budget gland enter the market that is affordable.... if you venture for more suitable alternative expect the reality check of expensive glands to enter the arena again.
Spent £50 on a panel receptical and Free-plug with extended screen clamp other day - extortionate just to connect a cable to a panel :O/