In the USA the supply line in the wall is typically a 1/2" line, which is then reduced at the stop valve.
Stop valves are described by the input size from the wall, then the discharge size, thus a stop valve designed to thread onto a 1/2" supply line and serve a 3/8 supply tube would be listed as a
1/2 FIP x 3/8 compression valve.
Supply valves are made with:
3/8", 1/2" & 3/4" FIP (female Iron Pipe thread inputs.)
1/2" sweat inputs (solder to copper)
1/2MIP & 1/2 sweat input (has both 1/2 male thread and 1/2 female solder fitting)
5/8" compression inputs (Will fit directly over 1/2 copper line with a mechanical compression fitting. Do not require soldering)
Stop valve are available with 1/4", 3/8" and 1/2" compression outputs
Typically the line from the stop valve to the faucett is 3/8 tubing although it is sometimes 1/4" tubing. To make the conversion from 3/8" to 1/4" we have to use a stop valve with a 1/4" discharge port. We also change the friction washer and cone washer from 3/8" to 1/4". The compression nut on the faucett will accept either one.
Out of convenience, in recent years most people have gotten away from using the flexible tubing and cone washer method and prefer to use the ready made supply lines but either one will work equally well, although i personally believe the cone washer and flexible tubing method is much cheaper and offers a longer service life. (In my jurisdiction the cone washer and flexible tubing method is required in commercial work)
You state that in Canada faucetts typically have a 1/2" flexible line. My question is, are you attempting to use a USA faucett in Canada, or convert a Canadian faucett to work in the USA?
Are the Canadian faucett 1/2" flex lines permanently attached to the faucett or are they threaded on the base of the faucett in the same manner as in the USA?
What material is the 1/2" flex made of?
