I'm not sure that 'skirting' woul;d look very good on the outside of an outdoor building ... and, assuming that you were thinking of installing it 'in the usual place', I would be concerned about having a cable, hidden behind 'skirting', so close to the ground in a garden - where the scope for traumatic damage is probably fairly high.Yes thanks John, would use conduit clips to retain it to the outside. Someone here mentioned false skirting that you can run cables behind. Might be a better option. Will have a look and report back.
If you used armoured cable (which is the usual way of supplying outhouses) you would not necessarily have to put it inside/behind anything - where above ground, it could simply be clipped to the wall.
Kind Regards, John.