The volume allowance for nonmetallic boxes is based on which of the following?

The volume allowance for nonmetallic boxes is determined primarily by considering the space needed for wiring devices and cable clamps. When installing electrical boxes, it is essential to ensure that there is adequate volume not only for the conductors passing through the box but also for the devices that will be installed within it, such as switches, outlets, or other components.

The National Electrical Code (NEC) specifies that the volume of the box must be sufficient to accommodate all of these elements without risking overheating or exceeding the box's electrical capacity. This includes accounting for the number of conductors entering the box and any internal fixtures, such as clamps, which could further occupy valuable volume.

Understanding the volume requirements helps ensure that the electrical installation is safe, functional, and compliant with code requirements.