So a 6-joule energizer that can energize 100 miles of fence wire would provide enough power for a 5-wire fence that’s 20 miles long (or a 4-wire fence that’s 25 miles long, and so on).

Typical fences are about 5 feet high, though any height is possible — I have a 7-foot-tall electric fence to keep out deer. ... Lightweight Electrified Poly Wire/Poly Tape. Installation: ...

The Star Inn in Cornwall put down yellow tape on the floor, and then the owner added an electric fence. He told CNN it seems more effective than rope or a chain. He says the fence is not turned on.