Indoor pull boxes should conform to the National Electrical Code (NEC). They should be constructed of sheet metal approved for all dry, interior and non-hazardous locations. For boxes in a wet, indoor areas, the National Electrical Manufacturers Association (NEMA) type 4 standard should be followed. The box should protect from incidental contact with the enclosed equipment, while protecting the equipment from falling dirt and splashed or hose-directed water.
These boxes house conduit communication cables. The dimensions of this type of box are based on the size and number of conduits housed. The pull box should be large enough to not force a significant bend or turn of the cables. Cables should be able to be pulled through the box without incurring damage.
Underground Pull Boxes
In-ground boxes should be grounded to their location and made of precast concrete or cast iron with galvanized steel or cast iron covers. The covers should be removable for access to the contained cables. Boxes should be able to withstand heavy traffic areas.
These boxes should also be rated NEMA 4 and be able to withstand dirt, rain, sleet and snow. They should protect the enclosed equipment when ice forms on the box. Boxes housing conduit materials should be made of galvanized metal or cast aluminum. Boxes housing PVC or plastic-coated materials should be made of fiberglass.