Article 200 — Use & Identification of Grounded (Neutral) Conductors

Article 200 makes the grounded conductor recognizable at a glance. Smaller conductors are white or gray, or have three continuous stripes; larger conductors can be re-identified at their terminations. The point is that anyone opening a box can trust the color and know which wire is the grounded one.

It also limits what you can do with a neutral: you generally cannot use a white conductor as a hot without re-marking it, and you cannot switch or fuse the grounded conductor in ways that would leave a circuit energized after it appears open. Continuity of the neutral is protected so downstream devices see stable voltage.

When it applies

Article 200 is about identifying and using the grounded conductor, usually the neutral. The color rules are here: white or gray, or three continuous white stripes, so that conductor is never mistaken for a hot. It also covers how to re-identify conductors when you have to and where the grounded conductor is and is not allowed to be switched or bonded.

Common mistakes

• Using a white wire as a hot in a switch loop without re-identifying it with tape or paint at both ends.
• Sharing neutrals between circuits in a way that overloads the grounded conductor.
• Confusing the grounded conductor with the grounding conductor, they sound alike but do very different jobs.

In the field

When I open an old box and find a white wire on a switch, I mark it before I do anything else. A neutral that is really a hot is exactly the surprise that gets the next person, so I make the label obvious for whoever comes after me.