We're thinking seriously about adding two (1-low and 1-high) hot wires to the outside of our existing fence for predators. It is 48" field fence with T & PT wood posts, and one strand of barbed wire about 4" above the field fence. So far all of the dogs that enter our property do so by going OVER the fence. Where is the best place to locate the top wire---above the barbed wire, or extending toward the outside? I assume the dog would have to touch two wires to get zapped, right? And is it possible to put the charger near the house rather than on the fence, so that you could check it without going out to the pasture (about 300 feet from the house)?