For equipment grounding conductors, the volume allowance is based on which conductor?

• A. The Largest Grounding Conductor
• B. The Sum Of All Grounding Conductors
• C. The Smallest Grounding Conductor
• D. No Matter Which

Answer: (A)

Box fill rules treat equipment grounding conductors (EGCs) specially. All EGCs inside a box are counted as a single conductor toward the box’s volume, and the size used for that single counted conductor is the largest EGC present. So, regardless of how many EGCs there are, the volume allowance you allocate equals the volume of one conductor the size of the largest grounding conductor in the box. This approach reflects that multiple grounding paths still share a single grounding function. For example, if you have several EGCs of different sizes, you would use the volume corresponding to the largest one to determine how much space the EGCs require.