In the US, code says you don't need a metal plate unless the wire is less
than 1 1/4 inches from the edge of the stud. There are no circumstances in a
regular 2x4 wall that would require a plate on both sides. Most of the time
you don't need one at all, if you drill your hole in the middle of the stud.
Usually people use these when you have to notch to run the wire near the
edge for some reason.

"Minnie Bannister" wrote in message
...
I know about the plates that one installs onto a stud where wiring
passes through it, but that is possible only on the side that is not yet
finished. What about the other side, the already-finished side? My
brother-in-law says that in Canada they use metal sleeves through the
studs, and the wiring then goes through the sleeve and is protected from
both sides. When I've asked here in the US, people say it sounds like a
great idea but they've never seen such a thing.

Are these available, and if so where?