Howard, you're advice is excellent! I've read that animals can sense the electricity (smell, sound, not sure it's been proven how) and they tend to avoid it once they know what it is. Maybe that's what they don't jump it? Hmm 🤔🤔
Aww, where's the fun in that :D :D I will never forget the day I...
If you look at the picture/attachment in Mtnboomer's post you will see the offset wires at the top. The fox jumps up, hits those wires which are extended out from the top, and is sent running. :)
That's why I said you need a positive and negative wire at the top. It will be a stronger shock...
Animals like foxes, coyotes, etc. will (most times) get very close to the fence then jump almost straight up and over.
I would recommend one strand 6 inches up (as suggested) and an offset top wire, preferably both a positive and negative wire, so if the animal jumps they get shocked.