Which of the following is a critical factor when determining box fill?

When determining box fill, one of the critical factors is the number of internal cable clamps. The National Electrical Code (NEC) stipulates specific volume allowances for boxes based on the type and number of conductors, as well as devices contained within the box. Internal cable clamps take up space inside the box and contribute to the overall volume, which can affect whether the box is compliant with box fill calculations.

Each internal cable clamp requires a certain volume allowance, which is added to the total fill calculation. Therefore, not accounting for cable clamps could result in exceeding the box's capacity, potentially leading to overheating and electrical hazards. This makes accurately considering the number of internal cable clamps a crucial aspect of ensuring safe and effective box fill management.

While the other factors may be relevant in various contexts, they do not directly influence the box fill calculations in the same way that the presence of internal clamps does. For example, the overall length of conductors and the gauge of the conductors are important for other aspects of electrical installation but have different implications on space requirements calculation compared to internal clamps. Similarly, while the number of devices may affect the fill as well, the direct impact of internal cable clamps on volume allowances makes them a particularly critical factor in determining box fill