What minimum distance must be maintained for the top of a box when it is supported by conduits according to NEC?

The minimum distance that must be maintained for the top of an electrical box when it is supported by conduits, according to the National Electrical Code (NEC), is 2 inches. This requirement exists to ensure that the top of the box remains accessible and that there is sufficient space for the wiring and any connections that may be made within the box. Maintaining this distance promotes safety by reducing the risk of damage to both the mechanical integrity of the box and the electrical components inside.

Additionally, this distance helps in ensuring proper heat dissipation and allows for easier installation or maintenance of the box and its connections. It reflects the NEC's broader emphasis on safe installation practices and the prevention of potential hazards associated with improper spacing and placement of electrical boxes.