Service conductors between meter box and 100 panel. Can I still use #2 Aluminum? Manitoba
The 23rd edition of the Canadian Electrical Code allows 2AWG aluminum service conductors for a 100A service if the conductor insulation is rated to 90˚C and the conductors terminate on equipment with maximum conductor termination temp of 75˚C (which includes all modern circuit breakers). 

These service conductors must also be carried in a minimum 1.25" conduit. If it's PVC conduit, the conduit must carry an SR (Sunlight Resistant) designation stamped on the outside.