Hey, welcome to the Forum!
The way the drum beat works here is first; you have to state as much information thats given in your work or school type question.
Second you have to tell the answer you arrived at; so that based on all the information, the forum people can all possibly answer to the question based on all the possible variables involved.
I don't know Canada's Code to point correctly to a Article number.
In The NEC-70 (05') searching the Index, there are plenty of definitions and various Articles.
You can also research various other threads that have been created here, combine and also use various words in the advance search. Review the low count respsonse to get a feel for what they asked to what was answered.
Hope that helps, Good Luck!