Wandering through the electrical aisle of my local big-box store, I see that it is now basically impossible to buy NM-B cable that doesn't adhere to this color coding:

  • 14 AWG = white jacket
  • 12 AWG = yellow jacket
  • 10 AWG = orange jacket

I understand the color coding, and it makes a lot of sense (I've got a mixture of 12 & 14AWG NM-B in my house and I really wish it was that easy to identify which was which when looking in a box). My question is two-fold:

  1. When did this become standard (in the US)?
  2. Is it an NEC requirement, or is it just a "standard" or "new tradition"?
  • Interestingly, I've now noted that at least one local retailer 12/3 is purple and 14/3 is light blue. I've not noted this at other retailers yet.
    – FreeMan
    Commented Apr 5, 2023 at 17:49

1 Answer 1


Type NM-B cable first began to be manufactured with color-coded jackets in 2001 to aid in identification of the conductor size. The color code that was introduced, which continues to be used today is as follows:

  • 14 AWG – White
  • 12 AWG – Yellow
  • 10 AWG – Orange
  • 8 AWG – Black
  • 6 AWG – Black​

This color coding system was developed to aid those who sell, install, and inspect Type NM-B cable so that the cable size can easily be identified, to reduce mistakes resulting from the use of an incorrect conductor size.

  • 1
    Is it an NEC requirement or is it simply convention?
    – FreeMan
    Commented Oct 5, 2020 at 13:44
  • Also, are both #8 & #6 black or was that a typo?
    – FreeMan
    Commented Oct 5, 2020 at 13:45
  • 1
    6&8 are both black the only addition would be for UF it is gray. It is not a requirement but was done to make it easier to see what your inventory is.
    – Ed Beal
    Commented Oct 5, 2020 at 13:52
  • 1
    @FreeMan -- it is conventional, for the reason Ed says. (UF is always grey, best I can tell) Commented Oct 5, 2020 at 23:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.