In the 2020 NEC ®, the requirements previously found in 314. This new section provides requirements for conductors and cables with an overall nonmetallic sheath or jacket entering boxes and enclosures. The National Electrical Code (NEC), published as NFPA 70, sets minimum safety standards for electrical junction boxes in residential and commercial buildings. In walls or ceilings constructed of noncombustible material (concrete, tile, etc. ), boxes must be installed so that the front edge will not be. The NEC has set limits on how far screws can protrude into boxes. (B) Depth of Outlet and Device Boxes with Enclosed Devices or Utilization Equipment.