As I was starting to say before my computer froze on me and I gave up on it temporarily…
If the thing is motored well enough and geared properly and – most important of all – designed for the duty service and capacity that you require – then an electric-powered machine should work just fine. I don’t even know of any hand-crank machines in this arena, and even they would have to be properly geared and probably couldn’t handle a sheaf of paper any bigger than an office-sized electric shredder could.
If capacity is what you’re after, you could always do one of these.
As you’ll see, after they shred the tire, they did some whole books, before they did the computer, etc. Have a blast. Keep your hands out.