What is the smallest size wire permitted for use in interior wiring?

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Having trouble with a homework question I see. Since you won't have access to help when you sit for the Journeyman's exam you need to learn how to locate answers in the code book for yourself.
To that end allow me to get you started/pointed in the right direction so to speak.
As wire is rated by ampacity you need to look at the tabs in your code book. See one that says "Ampacity"? T.310.16? Then flip back to the beginning of that Article (310) "Conductors for General Wiring". Read on until you find 310.5 Minimum Size of Conductors. Table 310.5 (Note the reference to "except as permitted elsewhere in this Code"). Keep reading until you feel confident you have followed all leads and references to Exceptions and Fine Print Notes.
The Key word in the question is "INterior" wiring.
Highlight and add tabs (post-it notes) along the way so that you don't miss anything. Flipping back and forth through the Code book can be time consuming, frustrating and confusing. But in the end it is very rewarding and empowering to be able to quote "Chapter and Verse" at the drop of a hat. I know this as I USED to be able to do that! 30 odd years of reading and following information provided on Blue Prints has robbed me of that skill. Now I have to reference the Code more often than not.
Here's a couple of hints that should help while studying and taking test.
A) use a lose leaf (ring binder) version of the code, this way you don't have to use one hand to keep the book open while doing calculations or reading several paragraphs. That will save you a LOT of time during a test.
B) make copies of all pertinent pages you find you reference frequently. By that I mean Table 310.16, 250.122, 314.16(A) to name a few. Place copies behind other pages throughout the code book. This way if a question starts you in say section 250 and you then have to reference 314 and then 310 you won't have to flip back and forth to find those other Tables and charts.
I sat for four County exams and no one noticed I had done so. Since I only copied existing pages I felt confident I wasn't "Cheating" and I did ask prior to my first exam. The folks giving the exam took a good look at the pages and scratched their heads. They admitted they had never seen that done before, but they allowed it. Saved me a TON of time.
C) use a straight edge to make lines in Tables so that as you read across the table you don't accidentally loose the line you are trying to read. No point in knowing how to do the math only to find you input the wrong information.
D) set time aside (each day) to study. Let friends and family know that you will be "out of touch" at that time. Turn off any distractions such as the Phone while you are studying. After and hour or so, take a break, check messages/text but put off responding until you are done with your homework. All that other stuff will wait. Really learning this material (getting good grades) is way more important down the road.
Would you go to a "Brain Surgeon" who Just managed to graduate Medical School?
Good luck to you in your pursuit to learn this Trade. It is a very interesting and challenging career.
(PS graduated #1 in my class, and passed all 4 test first time around. Now, if only I was "1/2 that smart" to this day!)...Show more

B. 14 awg Lediy99 has some good information for you, however in North Carolina the examiner provides the code book and a few other states this is also the case....Show more

Building codes in most states require 14 AWG. But I would recommend you use 12 AWG...Show more