NEMA Rating System
NEMA rating is a North American standard used to define the level of environmental protection for electrical enclosures. It is still commonly used, but is being replaced by the international IP standard.
| NEMA Rating | NEMA Definition |
|---|---|
| NEMA 1 | Intended for indoor use primarily to provide a degree of protection against contact with the enclosed |
| NEMA 2 | Intended for indoor use primarily to provide a degree of protection against limited amounts of falling water and dirt. |
| NEMA 3 | Intended for outdoor use primarily to provide a degree of protection against windblown dust, rain, and sleet; and to be undamaged by the formation of ice on the enclosure. |
| NEMA 3R | 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. |
| NEMA 4 | Intended for indoor or 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. |
| NEMA 4X | Intended for indoor and outdoor use primarily to provide a degree of protection against corrosion, windblown dust and rain, splashing water, and hose-directed water; and to be undamaged by the formation of ice on the enclosure. |
| NEMA 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. |
| NEMA 7 | Intended for indoor use in locations classified as Class I, Groups A, B, C, or D, as defined in the National Electrical Code. Type 7 enclosures shall be 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. Enclosed heat generating devices shall not cause external surfaces to reach temperatures capable of igniting explosive gas-air mixtures in the surrounding atmosphere. Enclosures shall meet explosion, hydro-static, and temperature design tests. |
| NEMA 9 | Intended for indoor use in locations classified as Class II, Groups E, F, or G, as defined in the National Electrical Code. Type 9 enclosures shall be 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. Enclosures shall meet dust penetration and temperature design tests, and aging of gaskets (if used). |
| NEMA 12 | Intended for indoor use primarily to provide a degree of protection against dust, falling dirt, and dripping noncorrosive liquids. |
| NEMA 13 | Intended for indoor use primarily to provide a degree of protection against dust, spraying of water, oil, and noncorrosive coolant. |