I have a great deal of experience in electrical/electronics. I spent 20 years in the Navy as an aviation electronics technician and yes, that means A LOT of wiring, not just black boxes (smile.)

We bought an old craftsman (about 1980-1920). One of the previous owners redid (most) of the wiring from old cloth covered knob and tube to ancient romex to modern romex. The problem(s) are snowballed.

He used mostly 12 awg for EVERTYTHING. He didn't upgrade the outlets and switches to handle 20 amps. He also I found out (not the hard way) that he left some of the old knob and tube alive and had many wires that were just spliced and even some that were just left hanging! I love my non-contact voltage sensor!

I went to my local big (orange) box home center and talked to a guy who did the electrical. His card said "Master Electrician". I doubt it though. H told me that almost no one used 15 amp breakers any more and that I could use a 20A and 12 awg wire, then tap off that in parallel with 14 awg to say the lighting circuits. So in effect, I have a 20 amp breaker, feeding a 20 amp capacity wire and tapping off to a 15 amp capacity wire and device. i.e. switch, outlet, etc...

I was skeptical, but did the design work. Then I went back to my books and training and could find NOTHING. I am going to the electrical inspector today for the city to verify my findings. I say this because I found several places I googled that gave caveats about "in some places" and "in certain exceptions".

Note that I have not run a single wire yet. I am somewhat anal about doing it once, doing it right and have no quams about ripping it out and starting over. I am upgrading to 200 amps, moving walls and increasing the number and quality of circuits and outlets/switches. Build for the future, build for expansion and document everything!

So what about it guys? Is he full of bull, can you point me to something official in writing I can reference or do I go back to the drawing board?

Support America's Disabled Veterans. We gave our all to protect America, so give us a hand. Disabled does not mean handicapped and handicapped does not mean unable.

Jerry J. US Navy (Ret.)

Any 14 gauge wire in the circuit would need the breaker to be reduced to 15 Amps.
Keep all wiring #12. You can use 15 amp recepticles.
He is probably not a Master, if he said #14 on a 20 amp breaker.

This is why you never go to the big orange box.

Strat's answer is correct. #12 is fine for everything on 20 or 15 amp breakers. If you use #14 for even the smallest run, that breaker will have to be 15 amp. Outlets can stay 15 amp even on 20 amp breakers.

TK is the expert here, you don't even need to find it in writing, whatever comes out of his mouth is better than any book.

USN, Used to do some Hazardous Work in Pensacola, Blue Angels would practice overhead, made Tuesday's Interesting. Take Care