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.
I don't believe there is anything in the code regarding your intention,
except that the breaker size would have to be reduced to protect the
smallest conductor or 15 amp in your case. IMO it is a poor practice, as
someone in the future can to easily replace the 15 amp breaker with a 20,
not being aware of what you've done
Nope. Others have already explained why you can't use #14 on a 20A circuit,
but I want to point out that backstabbed terminals aren't approved for use
with #14 wire in any case. They used to be... but not any more.
Doug Miller (alphageek at milmac dot com)
They were designed for both, but to allow the larger to be inserted, the
spring/holes had to be large enough which turned out to not be adequate
holding power in the long run for the smaller. Empirical data seems to
indicate the #12 is still adequate to not be such a problem so it hasn't
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.