richms:

 

Run it inside irrigation tube, that is like $7 for 20m of it at bunnings/miter10 and will give it some additional protection.

 

This or even a hose pipe. 

Ive got standard cable hanging on the outside of the house at the moment, has been there for about 3 months so far with no issues. Will be running some capping around soon thos so its out of the elements.. if it does fail at any point, cable is cheap to replace and easily accessible to re-run.