If you left it on 24/7 how would you know it failed? Anyway the answer to your question: There are two ways to power the BlacX up or down.
1.) The cheap and simple way is to yank the power plug out of the wall plug or reinstall it.
2.) The more elegant way, but will cost you a couple of dollars, is that GE makes a small gizmo that you plug into the wall plug and then plug the BlacX into that. The GE gizmo has a small standard wall switch built into it.
You don't need the switch as far as I know. If it fails off (open), you'll know. If it fails on, you'll not see anything different happen that would lead you to believe the switch is broken.