When we were very young (I don't know how
young, I was 8 or 9, my
sister would have been 4 or 5) my
parents had a
dog and a
garden. Those of you with dogs and gardens know that they cannot occupy the same
backyard at the same
moment in
time. Either the dog will destroy the garden, or the garden will have had to have moved to an alternate reality in order to escape the attack of the dog.
My parents, being familiar with the
delicate balance of the
space time continuum, chose to rope the garden off with an
electric dog fence. This produces a low voltage AC current between a
suspended
wire fence and the
ground. The circuit is completed by the dog. This field produces the needed alternate reality that the garden needs to survive.
It never worked really well, but my dad did set it up in the shop so the dogs wouldn't bug him, and he invited us children to see what it felt like. (yes - cement
is conductive) He would grab onto it, to show us it was ok, and then we all grabbed on - It felt weird, you could certainly feel the current and it was annoying, but not painful. We all let go, but my little sister couldn't. Her muscles weren't strong enough to overcome the spasm induce by the electrical current, and was forced (by the current) to hold on (the muscles for closing the hand are much stronger than those for opening the hand, if you must test a fence out for current (ie, don't ever do it), touch it with the back of your hand, not the tip of your finger - You'd be surprised how quickly your hand grabs the wire when that was not your intention. Ask me how I know...)
So we turned it off and comforted her (it's scary not to be able to move). We have
horse fencers now, and they produce about one zap per second. It gives the creature holding on a second to remove whatever appendage is in contact with the fence before the next zap. The dog fence was not considered dangerous enough to need that sort of safety...