I'm not sure if it's applicable in Canada, but in the states we have West Marine which is essentially a store for boaters (they are also online at
www.westmarine.com). They sell the Ancor brand of primary wire designed for marine applications, but it also complies with several UL and CSA specifications. It has a high strand count and is very flexible compared to traditional hook-up wire. We use welding wire for the heavy gauge applications (4 and 6 AWG), but for everything between 10 AWG and 20 AWG we use the Ancor stuff. It can be purchased by the foot or by the spool, which really helps keep costs down. Nothing worse than having $500 tied up in spools of wire that will take 10 years to use up.