It might not be a human, but here's a 22 on a squirrel. The right shot placement, and it would probably take down a person.
I'm happy to say that this isn't the states and we're not allowed to shoot intruders. If you're being robbed in your home. call the police and don't confront the robbers.
In Canada, defense with a firearm is considered, from what I recall in my law course is if you're in mortal danger. Otherwise if you fight someone, you gotta be on equal footing. like bat vs bat, fists vs fists.
Feel free to correct me if this is mis-information.
Whoa, apparently, you can fire warning shots, but expect a charge and acquittal, according to what happened in the link above.
Did a bit more research, here's a link with some situations and answers to defense.
http://www.cbc.ca/news/canada/self-d...-law-1.1229180
tl;dr
it's a grey area, you're allowed to use "reasonable force".