The National Electrical Manufacturers Association or NEMA is a U.S.-based association, which was created on September 1, 1926, when the Associated Manufacturers of Electrical Supplies and the Electric Power Club merged. It is headquartered in Rosslyn, Virginia. It sets many common standards used in electrical products among its over 400 members, and helps to develop and promote the International Electrotechnical Commission's standards in the U.S.[1]
NEMA has established a range of standards for electrical equipment enclosures. For more detailed and complete information, see the NEMA Standards Publication 250.
NEMA defines standards for many commonplace electrical interconnects, as well as outlining manufacturing standards for electrical products, such as various grades of electrical enclosures.
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NEMA Enclosur
NEMA defines standards for various grades of electrical enclosures typically used in industrial applications. Each is rated to protect against designated environmental conditions. A typical NEMA enclosure might be rated to provide protection against environmental hazards such as water, dust, oil or coolant or atmospheres containing corrosive agents such as acetylene or gasoline. A full list of NEMA enclosure types is available from the NEMA website.
| NEMA Type | Definition | IEC Equivalent |
|---|---|---|
| 1 | General-purpose. Protects against dust, light, and indirect splashing but is not dust-tight; primarily prevents contact with live parts; used indoors and under normal atmospheric conditions. | IP10 |
| 2 | Drip-tight. Similar to Type 1 but with addition of drip shields; used where condensation may be severe (as in cooling and laundry rooms). | IP11 |
| 3 and 3S | Weather-resistant. Protects against weather hazards such as rain and sleet; used outdoors on ship docks, in construction work, and in tunnels and subways. | IP54 |
| 3R | Intended for outdoor use. Provides a degree of protection against falling rain and ice formation. Meets rod entry, rain, external icing, and rust-resistance design tests. | IP14 |
| 4 and 4X | Watertight (weatherproof). Must exclude at least 65 GPM of water from 1-in. nozzle delivered from a distance not less than 10 ft for 5 min. Used outdoors on ship docks, in dairies, and in breweries. | IP56 |
| 5 | Dust-tight. Provided with gaskets or equivalent to exclude dust; used in steel mills and cement plants. | IP52 |
| 6 and 6P | Submersible. Design depends on specified conditions of pressure and time; submersible in water or oil; used in quarries, mines, and manholes. | IP67 |
| 7 | Hazardous. For indoor use in Class I, Groups A, B, C, and D environments as defined in the NEC. | — |
| 8 | Hazardous. For indoor and outdoor use in locations classified as Class I, Groups A, B, C, and D as defined in the NEC. | — |
| 9 | Hazardous. For indoor and outdoor use in locations classified as Class II, Groups E, F, or G as defined in the NEC. | — |
| 10 | MSHA. Meets the requirements of the Mine Safety and Health Administration, 30 CFR Part 18 (1978). | — |
| 11 | General-purpose. Protects against the corrosive effects of liquids and gases. Meets drip and corrosion-resistance tests. | — |
| 12 and 12K | General-purpose. Intended for indoor use, provides some protection against dust, falling dirt, and dripping noncorrosive liquids. Meets drip, dust, and rust resistance tests. | IP52 |
| 13 | General-purpose. Primarily used to provide protection against dust, spraying of water and noncorrosive coolants. Meets oil exclusion and rust resistance design tests. | IP54 |
See also
- NEMA connector
- Energy efficience
- COCIR
- International Electrotechnical Commission
- IP Code
References
- ^ "The IEC and NEMA", nema.org, accessed 2009-04-12
- ^ "NEMA/IEC enclosure ratings", Cole-Parmer Technical Library
External links
- National Electrical Manufacturers Association website
- NEMA Standards and Publications
- NEMA members
- Zentralverband Elektrotechnik- und Elektronikindustrie (ZVEI) (German equivalent to the NEMA)
- NEMA cable tray
- NEMA conversions to IP rating for Enclosures
- Nema table and information
- Custom NEMA and Outdoor Enclosure Solutions
- NEMA standards compared to European IP ratings
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