I don't think circuit sharing is the OP's question. He's asking if a Range OR a Dryer can be or ever could be fed with a cable that contained 2 insulated and 1 uninsulated conductors as long as they originated at the service rather than at a subpanel. I don't know about Canada, but when I started in the trade in 1983 in California we fed Ranges with 6/3 SEU all the time under those conditions. We used the bare aluminum strands twisted together as the 3rd conductor. This is no longer allowed but I still see it in older houses.
