In the 2023 NEC ®, new Section 314. 5 was added to ensure proper screws and fasteners are used where they enter the wiring compartment of an outlet box, device box, pull box, junction box, conduit bodies, fittings, and handhole enclosures. What are the specifications of screws for electrical equipment distribution boxes? What are the specifications of screws for electrical equipment distribution boxes? Distribution box screw specifications are generally M3, M4, M5, M6, M8, etc. Using the correct type and size of screw ensures components remain stable and that safety mechanisms, such as grounding, function as intended. Many people underestimate the importance of the National Electrical Code (NEC) guidelines.