There are two widely used standards for enclosure ratings. Nema enclosure ratings were created as the national standard for enclosures in the United States. Nema enclosure ratings were established by NEMA (National Electric Manufacturer Association). The international standard for enclosures was established by IEC (International Electric Codes).

Below are the standard Nema enclosure ratings for electrical equipment and IEC codes; both showing each of their descriptions. Manufacturers tend to offer electrical equipment in a number of different Nema and IEC enclosure ratings for safe operation in various environments.  In today’s international trade world, both standards are widely mentioned on a single product. (Example: NEMA 4X / IP 65). The most common Nema standards followed by IEC codes are shown below:

Nema Enclosure Ratings Type 1  are constructed for indoor use to provide a degree of protection to personnel against access to hazardous parts and to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt).

Nema Enclosure Ratings Type 12  are constructed (without knockouts) for indoor use to provide a degree of protection to personnel  against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and circulating dust, lint, fibers, and flyings); to pr ovide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (dripping and light splashing) and to provide a degree of protection against light splashing and seepage of oil and noncorrosive coolants.

Nema Enclosure Ratings Type 3R  are constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt); to pr ovide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (rain, sleet, snow); and, that will be undamaged by the external formation of ice on the enclosure.

Nema Enclosure Ratings Type 3RX  are constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid for eign objects (falling dirt); to pr ovide a degree of protection with respect to harmful ef fects on the equipment due to the ingress of water (rain, sleet, snow); that will be undamaged by the external formation of ice on the enclosure that provides an increased level of protection against corrosion.

Nema Enclosure Ratings Type 4  are constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and windblown dust); to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (rain, sleet, snow, splashing water, and hose directed water); and, that will be undamaged by the external formation of ice on the enclosure.

Nema Enclosure Ratings Type 4X  are constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt and windblown dust); to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (rain, sleet, snow, splashing water, and hose directed water); that provides an increased level of protection against corrosion; and that will be undamaged by the external formation of ice on the enclosure.

IP Codes – IEC Ratings

IEC outlines an international classification system for the sealing effectiveness of enclosures of electrical equipment against the intrusion into the equipment of foreign bodies (i.e. tools, fingers, dust) and moisture. This classification utilizes the letters IP (Ingress Protection) followed by two digits (example: IP 64).

 

 

 

 

 

 

 

 

 

 

The first digit indicates the degree that persons are protected against contact with moving parts (other than rotating shafts) and the degree that equipment is protected against solid bodies intruding into an enclosure. The second digit indicates the degree of protection of the equipment inside the enclosure against harmful entry of various forms of moisture (i.e. submersion, dripping, spraying).

To learn more about Nema enclosure ratings, visit either the Nema Website or IEC Website. For equipment repair and replacement quotes, call Precision Electric.

 

References: http://www.iec.ch/ 
https://www.deltat.com/enclosure_ratings.html 
https://www.nema.org/pages/default.aspx