Which insulation colors may be used for grounded circuit conductors?

• A. White or Gray
• B. Black
• C. Green
• D. Red

Answer: (A)

Grounded conductors are the neutral return path in a circuit, and their insulation is identified with light, non-energized colors so you can tell them apart from live and grounding conductors. White or gray insulation signals that this conductor is neutral and returns current to the source, which is why they’re used for grounded conductors. In contrast, green or green with a yellow stripe is reserved for equipment grounding, and black or red typically indicate hot (ungrounded) conductors. So white or gray is the appropriate color for a grounded conductor.