ECN Forum Forums Code Related Discussion NEC & other Code issues Marking conductors

Don- Look at 210.5(C) and we do have direction on identifying ungrounded conductors and I wonder if inspectors will allow two systems to have the same color ungrounded conductors and only change the color of the grounded conductors?

George,
Yes, if you have multiple systems, you have to identify the conductors by system, but the code does not specify how they are identified. If you choose to use black, red, blue for one system and black, red, blue with a tape mark you are in compliance with the code. The method is left totally up to the installer and the inspector has no say in it. The only other requirement is that the method of identification used be posted at every panel. Using the same color for ungrounded conductors or both systems without any other marking would be a violation. Note that under the 2005 code the required identification is only by system and not by phase so you could use all black for one system and all red for the other system. This will be corrected in the 2008 code.

I agree 100% with your comment Don, and as an inspector that's going to be my call. So in an existing building an installation of a second system, if it's a different voltage from an existing system or if we are installing 2 systems in a new building the rule applies.

I note that they make 4/C MC with two neutrals specifically for this purpose. Typically they have one conductor pair that is black and white, and the other pair is red and white with a red stripe. This eliminates any need for wanting to mark a second neutral in a 4/C cable. (Except, of course, for the situation where you don't have any of that kind a cable handy...)