In box fill calculations, how many counts do grounding conductors contribute?

• A. Grounds count as two.
• B. Grounds are not counted.
• C. Every grounding conductor counts separately.
• D. Grounds count as one.

Answer: (D)

In box fill calculations, grounding conductors are counted as a single conductor for the entire box. This is because they don’t carry normal operating current, and all equipment grounding conductors in a box are tied together to provide a single grounding path. So, regardless of how many grounding wires enter the box, they collectively count as one toward the required fill volume. Other conductors (hot and neutral) are counted individually, and any internal clamps may add their own count, but the grounding group stays as one. For example, even if there are several ground wires, they all count as one in the box fill total.