Enclosures

Equipment enclosures are described in NEMA standard ICS 1 110. Briefly, the designer may be expected to encounter Type 1, Type 4, and Type 12 enclosures most often. Type 1 is a general-purpose indoor, ventilated enclosure that protects personnel from accidental exposure to high voltages and protects equipment from dripping water. Type 4 is a watertight, dusttight, nonventilated indoor or outdoor enclosure. Type 12 is a dusttight, driptight indoor enclosure. Type 12 may have nonventilated sections that are dusttight and ventilated sections that are not.

Most enclosures are made with 10 to 12 ga steel, although smaller wall mount cabinets may be 14 ga. Corners and seams are welded, and free-standing enclosures are equipped with three-point door latches. The rear wall of a cabinet has welded studs that support a removable panel so that component assembly can be done outside the cabinet. All doors should be connected to the enclosure frame with flexible grounding straps for safety. The industry standard for free standing enclosures is 90 inches in height.