Unless the wire is #4. Then re-identification is allowed. However, some supply houses don't have #6 in any color but black, so you are forced to make a minor code violation just to identify the wire!
So is this to indicate you can't simply mark a bundle of black hot wires to indicate separate circuits for easy identification in junction boxes? What I mean is to identify them as separate circuits, not to re-identify the use of the wire (neutral/ground). I uderstand you can't take a #6 wire that is all black and re-color code it white to use it as a neutral (or green for a ground).
I don't really want to beat this thread to death over wire colors. My response was originally to Allan's post about the color of the wire can be MARKED with anything that is not green in color.
Originally Posted by InPhase277
I will add the qualifier that this is only in a listed cable assembly. An already white wire couldn't be used in a switch loop if it were pulled into a conduit as an individual conductor.
This makes perfect sense. Thanks for adding that clarification. I would hope no one would do this in a run of conduit, might get quite the surprise otherwise.
Stubbie, No worries. I do fully understand the marking of the white wire in a switch loop when using romex (black being the most common color).