NEMA ENCLOSURE DEFINITIONS

NON-HAZARDOUS LOCATIONS
Type 1—Enclosures are intended for indoor use. Primarily used to provide a degree of protection against limited amounts of falling dirt.

Type 4—Enclosures are intended for indoor and outdoor use. Primarily used to provide a degree of protection against windblown dust and rain, splashing water,
Hose-directed water and damage from external ice formation.

Type 3R—Enclosures are intended for outdoor use, primarily to provide a degree of
Protection against falling rain and to be undamaged by the formation of ice on the enclosure.

Type 12—Enclosures are intended for indoor use. Primarily used to provide a degree of protection against circulating dust, falling dirt, and dripping non-corrosive liquids.

HAZARDOUS (CLASSIFIED) LOCATIONS—See NEC Explosive Atmosphere Classifications Below

Type 7—Enclosures intended for indoor use in locations classified as Class I, Groups A, B, C, or D as defined by National Electric Code.

Type 9—Enclosures intended for indoor use in locations classified as Class II, Groups E, F, or G as defined by the National Electric Code.

NATIONAL ELECTRICAL CODE EXPLOSIVE ATMOSPHERE CLASSIFICATIONS

Certain locations are hazardous because the atmosphere does or may contain gas, vapor or dust in explosive quantities.

The National Electrical Code (NEC) divides these locations into Classes and Groups according to the type of explosive agent which may be present. Listed are some of the agents in each classification. For complete list, see NFPA (National Fire Protection Association) publication 497M.

Underwriters’ Laboratories tests motors and other devices for safety in explosive atmospheres, and publishes a list of those meeting its standards for each Class and Group. Use of UL Listed devices does not necessarily make an installation conform to the NEC or local codes. Consult Chapter 5 of the NEC, local building codes, OSHA requirements and insurance inspectors for detailed data as to proper procedures.

CLASS I

Group A: Acetylene.
Group B: Butadiene, ethylene oxide, hydrogen, propylene oxide, manufactured gases containing more than 30% hydrogen by volume.

Group C: Acetaldehyde, cyclopropane, diethyl ether, ethylene.
Group D: Acetone, acrylonitrile, ammonia, benzene, butane, ethanol, ethylene dichloride, gasoline, hexane, isoprene, methane (natural gas), methanol, naphtha, propane, propylene, styrene, toluene, vinyl acetate, vinyl chloride, xylene.

CLASS II
Group E: Aluminum, magnesium and other metal dusts with similar characteristics.
Group F: Carbon black, coke or coal dust.
Group G: Flour, starch or grain dust.

CLASS III
Easily ignitable fibers, such as rayon, cotton, sisal, hemp, cocoa fiber, oakum, excelsior and other materials of similar nature.
 

 Battery Enclosures