When up to four equipment grounding conductors enter a box, what volume allowance shall be made based on the largest equipment grounding conductor?

When determining the volume allowance for equipment grounding conductors entering a box, the National Electrical Code (NEC) mandates recognizing the largest equipment grounding conductor present among those entering the box. Specifically, when there are up to four equipment grounding conductors, only the volume equivalent to a single equipment grounding conductor needs to be added to the box volume calculation. This approach streamlines the volume requirements, allowing for a more practical and efficient design process without overcomplicating the box fill calculation.

The NEC takes into consideration that the grounding conductors, especially when they are of varying sizes, do not all need to be counted fully toward box volume, which can significantly impact box sizing. Therefore, acknowledging just a single equipment grounding conductor's volume simplifies compliance while ensuring safe and adequate grounding practices.