NEMA Classifications
The National Electrical Manufacturers Association (NEMA) has standards for the construction of electrical enclosures for installation in non-hazardous and hazardous locations.
NEMA Electrical Enclosure Classifications:
Type 1 - Intended for indoor use primarily to provide a degree of protection against contact with the enclosed equipment where unusual service conditions do not exist.
Type 2 - Intended for indoor use primarily to provide a degree of protection against limited amounts of falling water and dirt. They are not intended to provide protection against conditions such as dust or internal corrosion.
Type 3 - Intended for outdoor use primarily to provide a degree of protection against windblown dust, rain, sleet; and to be undamaged by the formation of ice on the enclosure. They are not intended to provide protection against conditions such as internal corrosion or internal icing.
Type 4 - Intended for outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, and hose directed water; and to be undamaged by the formation of ice on the enclosure. They are not intended to provide protection against conditions such as internal corrosion or internal icing.
Type 4X - Same as Type 4 enclosure but provides additional corrosion protection.
Type 5 - Intended for indoor use primarily to provide a degree of protection against settling airborne dust, falling dirt, and dripping non-corrosive liquids. They are not intended to provide protection against internal corrosion.
Type 6 - Intended for indoor or outdoor use primarily to provide a degree of protection against the entry of water during temporary submersion at a limited depth; and to be undamaged by the formation of ice on the enclosure. They are not intended to provide protection against conditions such as internal corrosion, internal icing, or corrosive environments.
Type 7 - Capable of withstanding the pressures resulting from an internal explosion of specified gases, and contain such an explosion sufficiently that an explosive gas-air mixture existing in the atmosphere surrounding the enclosure will not be ignited.
Type 8 - Arranged internally so that all arcing contacts, connections, etc, are immersed in oil. Arcing is confined under the oil such that is will not ignite an explosive mixture of gases in internal spaces above the oil or in the atmosphere surrounding the enclosure. Enclosed heat generating devices shall not cause external surfaces to reach temperatures capable of igniting explosive gas-air mixtures in the surrounding atmosphere. Enclosures intended for outdoor use shall also meet the requirements of Type 4.
Type 9 - Capable of preventing the entrance of dust. Enclosed heat generating devices shall not cause external surfaces to reach temperatures capable of igniting or discoloring dust on the enclosure or igniting dust-air mixtures in the surrounding atmosphere.
Type 10 - Capable of meeting the requirements of the Mine Safety and Health Administration, 30 C.F.R., Part 18.
Type 11 - Intended for indoor use primarily to provide a degree of protection against the corrosive effects of liquids and gases. They protect the enclosed equipment against the corrosive effects of fumes and gases by providing for the immersion of the equipment in oil. They are not intended to provide protection against conditions such as internal condensation or internal icing.
Type 12 - Intended for indoor use primarily to provide a degree of protection against dust, falling dirt, and dripping non-corrosive liquids. They are not intended to provide protection against conditions such as internal condensation or internal icing.
Type 13 - Intended for indoor use primarily to provide a degree of protection against dust, spraying of water, oil, and non-corrosive coolant. They are not intended to provide protection against conditions such as internal condensation or internal icing.