I use velcro. Stick a patch of the rough stuff on the floor (make sure it sticks reallllly well since you don't want it coming loose and sticking to your snake) and take a strip of the soft stuff and wrap it around the wire so it's stuck to itself like a flag.
now you can just velcro it to the floor patch. the snake will be able to pull it loose if it tries hard enough, but you can just stick it back down when he does. if it's under the substrate it will be easier to prevent that.