When counting the number of conductors in a box, how is a conductor running through the box with an unbroken loop counted?

When determining the volume allowance in a junction or outlet box according to the National Electrical Code (NEC), a conductor running through the box with an unbroken loop is counted as two conductor volumes. This is because the conductors create a pathway that necessitates space within the box for both the entry and the exit of the electrical conductors.

The NEC specifies that when a conductor passes through a box without being connected at any terminal (like a loop), it effectively occupies space for both the incoming and outgoing segments of that conductor. Therefore, it is essential to consider that each segment contributes to the overall need for volume within the box to ensure proper installation practices, reducing the risk of overheating and facilitating safe operation.

This counting method ensures that the box can accommodate all the conductors safely, providing adequate space for heat dissipation and preventing overcrowding, which could present a fire hazard. It's crucial to adhere to these guidelines to comply with safety codes and regulations outlined in the NEC.