Overview
In non-hazardous locations, there are several different NEMA ratings for specific enclosure “types”, their applications, and the environmental conditions they are designed to protect against when completely and properly installed. The following provides an overview of the NEMA Enclosure Types.
Enclosure types 7, 8, 9, and 10 are for hazardous locations and are not included in this article.
For complete official definitions, descriptions, and test criteria, see the National Electrical Manufacturers Association (NEMA) Standards Publication No. 250.
Enclosure Types
NEMA 1
(Sometimes known as a “finger-tight” enclosure. This is the least costly enclosure, but is suitable only for clean, dry environments)
Enclosures constructed for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment
Provide a degree of protection against falling dirt
NEMA 2
Same as NEMA 1 including protection against dripping and light splashing of liquids
NEMA 3
Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment
Provide a degree of protection against falling dirt, rain, sleet, snow, and windblown dust
Will be undamaged by the external formation of ice on the enclosure
NEMA 3R
Same as NEMA 3 excluding protection against windblown dust
NEMA 3S
Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment
Provide a degree of protection against falling dirt, rain, sleet, snow, and windblown dust
External mechanism (s) remain operable when ice laden
NEMA 4
Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment
Provide a degree of protection against falling dirt, rain, sleet, snow, windblown dust, splashing water, and hose-directed water
Will be undamaged by the external formation of ice on the enclosure
NEMA 4X
(This is the most common enclosure in “food” environments)
Same as NEMA 4 including protection against corrosion
NEMA 5
Enclosures constructed for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment
Provide a degree of protection against falling dirt, settling airborne dust, lint, and fibers
Provide a degree of protection against dripping and light splashing of liquids
NEMA 6
Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment
Provide a degree of protection against falling dirt, hose-directed water and the entry of water during occasional temporary submersion at a limited depth
Will be undamaged by the external formation of ice on the enclosure
NEMA 6P
Same as NEMA 6 including protection against the entry of water during prolonged submersion at a limited depth
NEMA 12
(This is the most common type of enclosure used in normal factory environments)
Enclosures constructed (without knockouts) for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment
Provide a degree of protection against falling dirt, circulating dust, lint, fibers, and against dripping and light splashing of liquids
NEMA 12K
Same as NEMA 12 including enclosures constructed with knockouts
NEMA 13
Enclosures constructed for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment
Provide a degree of protection against falling dirt, circulating dust, lint, fibers, and against the spraying, splashing, and seepage of water, oil, and non-corrosive coolants
Have a question or having difficulties? Talk to Dave Schall, our PRIMUS sterilizer expert who is here to assist you anytime at 877.679.7800 extension 1212 or email at dschall@spire-is.com.
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