For a pull box with a rigid metal conduit that has a removable cover, what is the required minimum depth from the entry wall to the cover?

For a pull box that utilizes a rigid metal conduit and features a removable cover, the National Electrical Code (NEC) specifies a minimum depth requirement from the entry wall to the cover of 4 inches. This depth is necessary to ensure that there is adequate space for the conductors and connections that may be housed within the pull box.

Having a minimum depth of 4 inches helps to prevent damage to the wiring during installation or maintenance and provides sufficient room for pulling wires, which is essential during wiring installations. Ensuring this depth also adheres to safety standards, allowing for proper functioning while minimizing the risk of overheating due to cramped space for electrical connections and wire management.

The other options do not meet the NEC requirements for pull boxes with removable covers, as they either provide insufficient space or exceed the necessary depth without offering any tangible benefit for functionality or safety.