Nema 4 – FAQ

Who or what is NEMA?

NEMA is the National Electrical Manufacturers Association (USA) and they provide a designation for enclosures, including computer enclosures as guidance to the level of protection they offer. NEMA is the United States equivalent of the International organisation IEC (International Electrotechnical Committee). The IEC issue IP ratings (Ingress Protection) that are commonly used throughout Europe and outside North America, NEMA issue their own rating.

What is the difference between the IEC IP rating and the NEMA system?

The IEC designation consists of the letters IP followed by two numerals, the first numeral indicates the degree of protection provided by the enclosure with respect to solid foreign objects  while the second characteristic numeral indicates the degree of protection provided by the enclosure with respect to the harmful ingress of water.  The NEMA code is a single number that suggests the total level of protection an enclosure can offer.

What NEMA enclosure rating is the equivalent of IP 65?

It is not possible to state that an IP rating is equivalent to a NEMA code as an IP rating only considers protection against solid foreign objects and water while the NEMA codes consider these but also other items such as corrosions and construction details.  For this reason IT IS possible to say that a NEMA Type is equivalent to an IP rating but it IS NOT possible to state that an IP rating is equivalent to a NEMA code. To the question of IP 65 a type 6 and a type 6P meet or exceed an IP 67. They would therefore meet an IP 65.

What are the most common NEMA codes for computer enclosures?

The two most common codes designated to computer enclosures are NEMA 4 and NEMA 4 is a computer enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt, rain, sleet, snow, windblown dust, splashing water, and hose-directed water; and that will be undamaged by the external formation of ice on the enclosure. NEMA 4X is a unit constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt, rain, sleet, snow, windblown dust, splashing water, hose-directed water, and corrosion; and that will be undamaged by the external formation of ice on the enclosure.

This post was written by Richard N Williams

Richard N Williams

Richard N Williams is a writer and journalist based in Birmingham, UK. He has many years of experience writing about all aspects of the internet and digital technology. He is the author of several technology related books and his articles have appeared in various publications, trade magazines and online journals. Richard N Williams Google+

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