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Code Quandaries

May 1, 2000 12:00 PM, By Mike Holt, NEC Consultant

Here are the latest short answers to questions posted on our Web site. In our discussion, we will cover topics from Secs. 200-6(d), 210-4(d), 210-5(a), 215-8, 230-56, 250-122(c), 384-3(e) and Table 250-122 of the National Electrical Code (NEC).

Q. Does the NEC require you to color code phase conductors?

A. No. There is no NEC rule requiring color coding of phase conductors, however Sec. 210-4(d) states "where more than one nominal voltage system exists in a building, each ungrounded conductor of a multiwire branch circuit, where accessible, shall be identified by phase and system. This means of identification shall be permitted to be by separate color coding, marking tape, tagging, or other approved means and shall be permanently posted at each branch-circuit panelboard."

This rule applies primarily for commercial and industrial buildings that have 208Y/120V for receptacle circuits and 480Y/277V for lighting and other equipment loads.

If two system voltages are not present, then the NEC doesn't require identification of multiwire branch circuits.

Note: You must identify the high-leg conductor with the color "orange." (See Secs. 215-8 for feeders, 230-56 for service conductors, and 384-3(e) for switchboards or panelboards.) When you install two voltage systems in the same raceway (or enclosure), one system's neutral can be white or natural gray and the other system's neutral must be white with a readily distinguishable different color stripe (other than green), or identified with other effective means. [See Secs. 200-6(d) and 210-5(a).]

Q. Can I use a single equipment-grounding conductor for a nonmetallic raceway containing multiple circuits?

A. Yes. Sec. 250-122(c) covers this issue. When you install multiple circuits in the same raceway, you can use a single equipment-grounding conductor for all circuits. The single equipment-grounding conductor is sized to the largest overcurrent device protecting the conductors in the raceway, in accordance with Table 250-122.