Article 312 Cabinets, Cutout Boxes, and Meter Socket Enclosures

312.1	Scope

I. Installation

312.2	Damp, Wet, or Hazardous (Classified) Locations

When installed in wet locations, they must be weatherproof. In damp or wet locations, surface boxes must prevent moisture from entering and have at least 6 mm (¼ in.) of air space between it and the wall or support. Raceways or cables entering above uninsulated live parts in enclosures in wet locations must use fittings listed for wet locations. Nonmetallic enclosures can be installed on concrete, tile, or masonry without an airspace. In hazardous locations conformance must be made with the requirements of Articles 500 through 517.

312.3	Position in Wall

When installed in noncombustible material, they may be set back 6 mm (¼ in.) When installed in combustible material, they must be flush with the surface.

312.4	Repairing Plaster and Drywall or Plasterboard

If a plaster, drywall, or plasterboard surface is broken or incomplete it must be repaired so that there are no open spaces or gaps larger than 3 mm (¼ in.) at the edge of the cabinet or cutout box that employs a flush-type cover.

312.5	Cabinets, Cutout Boxes, and Meter Socket Enclosures

The opening must be closed. When metal cabinets, boxes, or enclosures are used with open wiring or knob-and-tube work, the conductors must come in through an insulated bushing. In dry areas, they may enter through flexible tubing. Cables must be secured to the box. There is an exception.

312.6	Deflection of Conductors

Refer to Tables 312.6(A) through (C) in the NEC® for minimum width of gutters and bending spaces.

312.7	Space in Enclosures
312.8	Enclosures for Switches or Overcurrent Devices
312.9	Side or Back Wiring Spaces or Gutters

II. Construction Specifications

312.10	Material

If metal, it must have corrosion protection. Sheet steel cabinets must be at least 1.35 mm (0.053 in.) thick uncoated. Nonmetallic cabinets must be approved by the authorities.