wrote in message
ups.com...
I've got a 20A circuit, #12 wire for the feed the outlets (4 of them).
I would like to add a switch and tap the outlet to feed the light
switch (in a closet).

Is it up to code to use a #14 (either back-stabbed or screwed-on) to
feed the switch? I realized that mixing wire gauges is not always good
practice. However, I've got a lot of left-over #14 that can be used
for the short run.

Mixing gauges is fine; I just ran a circuit partly in #10 and #12 because I
wanted to minimize voltage drop. But it was a 20a circuit.
Your problem is that #12 is the minimum for a 20a circuit.
You can reduce the breaker to 15a.