With due respect to Don Firth, I think there are chords that comes up from time to time that cannot be played without wrapping the thumb around, but they are few and far between. ;-)

The reality is that basic classical guitar technique and basic electric guitar technique are pretty much the same. There are a a lot of advanced classical guitar things that one will likely never use(though you could)--but the bottom line stuff is the same. There is a very simple reason for this--the underlying logic of the fretboard is the same.

Twenty odd years ago, when I began teaching guitar classes, I called up lots of people who I'd known over the years who used to play guitar and didn't anymore, to find out why this was so--There was one answer--as time went by, their musical tastes changed, and they couldn't adapt their playing to the kind of music they liked--

The reason for that was simple--they had learned the specifics that they needed for a given style, but they'd never learned the basics--

That is, they could play Mississippi John Hurt's "Candyman" note for note, but couldn't play a simple quarter note scale, couldn't locate notes on the fretboard, couldn't play intervals, couldn't play a melody, and could't read music or follow a chord chart in time--

Anyway, I wanted to let Don know he isn't the only one who thinks that way--