Gary,
Depending on the type of wire/insulation you use, the
insulation can certainly come off. Forgot the name of it
but it usually has a color coat then a clear insulation.
The clear insulation does come off, looks like a snake
shedding it's skin. The color insulation (under the clear
stuff) hasn't come off yet, but it's only been up about
10 years. The antenna does run through trees and I'm sure
some of the insulation has rubbed off. It doesn't seem to
affect things, so I don't really care...
'Doc