On Monday, September 28, 2015 at 12:58:21 AM UTC-5, wrote:
On Sun, 27 Sep 2015 19:56:38 -0700 (PDT), Uncle Monster
wrote:

The breaker is there to protect the wiring. I you're really worried about overloading the circuit, you can feed the switch with #12 then split the lights into two strings wired with #14.

That is not legal on a 20a circuit, even if it works.

Yea I know and have never done it. The last time I wired a whole building I used #14 and #12 stranded THHN in EMT. I knew you'd be the expert on the code but I don't understand what the OP is worried about if he uses LED lighting. The A19 60w bulb equivalent draws 10 watts or less and the 100 watt equivalent LED bulb uses 14.5 watts. If he lit his whole house with LED bulbs it would probably draw less than 20 amps total. I find it hard to believe he'd put 75w bulbs in every fixture and run them all at the same time. If his fixtures are capable of using 75w bulbs, is it a code requirement that the lighting circuit be capable of powering all 13 fixtures at the same time if 75w bulbs are used?
I don't know where my Ugly's Electrical Reference Book is and it's not the newest edition anyway. ^_^

[8~{} Uncle Curious Monster