White wires with blue stripes indicate which type of conductor?

• A. AC grounded conductor
• B. DC grounded conductors
• C. Equipment grounding conductor
• D. Externally powered conductor

Answer: (B)

In electrical wiring, color codes signal what a conductor is doing. White (or gray) generally marks a grounded conductor, like a neutral in AC systems. When that white insulation carries a blue stripe, it’s used to identify a DC grounded conductor—the return path in a DC circuit. The blue stripe distinguishes it from an AC neutral and from other types of conductors.

It’s not the equipment grounding conductor, which is green or bare, and it’s not an externally powered (hot) conductor, which would be a live conductor colored to indicate power. So the white with blue stripe specifically indicates the DC grounded conductor.