Allegheny2-6-6-6
Check your local code but here code specifies #14 for lighting and interior receptacles.I wired my entire shop with #14 and used #12 for the 220 line for the compressor and the electrical inspector went away smiling so I guess I did it right.
Obviously I can't speak about your local code for sure (since local jurisdictions can ad or change code requirements), BUT, the NEC does not PREVENT one from using 20 amp/#12 wiring for lighting and receptacle circuits. It simply allows 15 amp/#14 to be used for that purpose.
Most residential wiring is done with mostly #14 for economy and speed/ease of installation, but larger, higher end homes often take advantage of the reduced number of circuits required by using 20 amp circuits. My completely restored 1901 Queen Anne home has all the lighting and receptacle circuits wired with ALL 20 amp circuits/#12 wire, installed by me during the complete restoration of the home and the Inspector said it was one of the best jobs he had ever seem - quite the oposite from "specifies #14 for lighting and receptacles".
To the OP, as the other qualified electrican on here said, a 15 amp circuit with #14 wire would be fine, but if you want you can use the #12 with a 20 amp or 15 amp breaker.
To the other poster who commented about too large a wire size and failing an inspection - not completely true, you have over simplified the facts. Virtually all 15 amp breakers are rated for up to #12 or #10 wire, which in commercial applications may be needed for long runs because of voltage drop. SO, if I bring a #12 wire into a pannel, and connect it to a 15 amp breaker who's connections are rated for #12 wire (or larger in some cases), it would be completely code legal and pass inspection.
Every time one of these questions come up on here, there is lots of miss-information, but, as many do suggest, if you don't know, get an skilled professional.
Sheldon
Electrical Designer, Electrician, Residential Architectural Designer, Old House Restoration Consultant, HVAC Designer, Old House Master Carpenter, Plumber
