What factor contributes to the required number of volume allowances in a box containing fixtures and devices?

The number of volume allowances in a box containing fixtures and devices is influenced by the gang required for the mounting. This refers to how many devices or fixtures will be mounted in that box, which directly affects the amount of space needed to safely accommodate wiring and connections without overcrowding.

Each device or fixture in the box requires a specific amount of volume to ensure proper installation and function, as well as compliance with safety standards defined in the NEC. For example, when multiple devices are housed in one box, the volume must be increased to allow for the additional wires and connections, which, in turn, affects heat dissipation and accessibility.

While factors such as the number of conduits entering the box, the height, and the width of the box do play roles in determining overall box size and capacity, it is the gang configuration that primarily dictates the required number of volume allowances. Understanding the mounting requirements is crucial for ensuring that the box can accommodate all installed components safely and effectively.