NEMA (National Electrical Manufacturers Association) defines standards used in North America for different grades of electrical enclosures. Such enclosures are mostly used in industrial environments,harsh work conditions,and hazardous locations. NEMA ratings categorizes enclosures according to their ability to withstand damaging substances like water, dust, corrosion, oil, or other foreign materials.
NEMA Ratings
As mentioned above, NEMA ratings define standards for electrical enclosures and define environment the enclosure can be used in with its ability to withstand harsh work conditions. However,NEMA do not test products nor it is associated with any testing laboratories, it only defines and publishes enclosure standards.Manufacturers can self declare their compliance or use third party testing agencies for certification. Below is the description about non-hazardous and hazardous locations NEMA enclosures types and their purpose.
Non-Hazardous locations
| Type | Purpose |
| 1 | Enclosures constructed for indoor use and provide protection against incidental contact and dirt. |
| 2 | Enclosures constructed for indoor use and provide protection against falling dirt, dripping and light splashing of liquids. |
| 3 | Enclosures constructed for both indoor or outdoor use and profile protection against dirt, rain, and snow. |
| 3R | Enclosures constructed for indoor/outdoor use and provide protection against falling dirt, rain, dust, sleet, and snow. |
| 3S | Enclosure constructed for indoor/outdoor use provides protection against dirt, windblown dust, water ingress (rain, snow, sleet). |
| 4 | Enclosure constructed for indoor/outdoor use and provides protection against dirt, rain, sleet, snow, dust, and water. |
| 4X | Enclosures constricted for indoor/outdoor use and provide protection against falling dirt, rain, sleet, snow, windblown dust, and splashing water. |
| 5 | Enclosures constructed for indoor use and provide protection against dirt, dust, lint, fibers, flyings, dripping and splashing liquids. |
| 6 | Enclosures constructed for indoor/outdoor use and provide protection against falling dirt and water |
| 6P | Enclosures constructed for indoor/outdoor use and provide protection against foreign object like dirt, water ingress and additional protection against corrosion. |
| 12K | Enclosures constructed for indoor/outdoor use and provide protection against dirt, circulating dust, lint, fibers, flyings, dripping water, oil seepage and non-corrosive coolants. |
| 13 | Enclosures constructed for indoor use and provide protection against dirt, circulating dust, lint, fibers, flyings, oils, and non-corrosive coolants. |
Hazardous Locations
| Type | Purpose |
| 7 | Enclosures constructed for indoor use in hazardous classified locations Class I, Division 1,Groups A,B,C, or D. |
| 8 | Enclosure constructed for indoor or outdoor use in hazardous locations classified Class I, Division 1,Groups A,B,C, and D. |
| 9 | Enclosures constructed for indoor use in hazardous location classified as Class II, Division 1,Groups E, F, or G. |
| 10 | Enclosures constructed to meet requirements of mines safety and health. |
This was the overview of NEMA enclosures and it types. NEMA performance and test methods are opted by Underwriter Laboratories (UL) and the Canadian Standards Association (CSA) as a medium for listing electrical enclosure. The enclosures further carry a label by UL or CSA to indicate they have passed the test and meets UL and CSA applicable standards.