Terry: Allow me to be pedantic here. CANADA does not run any scales. They are run by the province. I have to assume that when you refer to "Canada" you are most likely refering to ONTARIO.
I have no idea and in a quick search couldn't find anything but here is the link to the Ministry of Transport of Ontario website.
http://www.mto.gov.on.ca/english/trucks
>C5BILL:
>
>On my first visit to Canada, many years ago, I stopped at an
>Ontario scale and asked the scalemaster if my van was
>required to scale there. He said "no, not unless I wanted
>to stop by". I've never entered a scale in Canada since nor
>have I been challenged to do so. Perhaps scalemasters in
>different Provinces would provide different comments.
>
>Not having a written copy of the law, I'd suggest you stop
>and satisfy yourself in the same manner. You'll feel better
>as you pass the rarely opend scales.
>
>Terry