Specific Applications of Enclosures for Outdoor Nonhazardous Locations
The purpose of this page is to provide general information on the definitions of NEMA Enclosure Types to architects, engineers, installers, inspectors and others of NEMA Standards Publication 250-2003 in enclosures for outdoor nonhazardous location applications. We provide a comparison of NEMA in a chart, table compare. Generally, NEMA enclosures are categorized by their level of protection from 1 to 13. They have advantages and disadvantages relative to each other; these are very easy to understand by definitions defined by NEMA and UL organizations. However, in order to specify the right enclosures suitable for your application, you need to know where enclosures will be located first. Therefore, we will inform you about NEMA enclosures that generally are constructed for outdoor nonhazardous locations. A non-hazardous location is an area in which an explosive atmosphere is not expected to be present in quantities such as to require special precautions for the construction, installation, and use of equipment. For more information about hazardous and non-hazardous definitions .
Note: To understand the standards: NEMA and UL are standards-writing organizations. The ratings are categorized on similar application descriptions and performance expectations to provide the level of protection to electronics inside the particular enclosures. UL (Underwriters Laboratories) requires testing for compliance by qualified evaluators independent of the manufacturer. NEMA, on the other hand, does not require independent testing and leaves compliance up to the manufacturer.
There are 10 NEMA types that generally are constructed for this environment which are listed below. Note: Generally, enclosures constructed for outdoor nonhazardous locations are suitable for indoor applications too; however, you could save money by choosing other NEMA types that apply only to indoor nonhazardous locations.
| Enclosure Rating | National Electrical Manufacturers Association (NEMA Standard 250) |
Underwriters Laboratories, Inc. (UL50 and UL 508) |
|---|---|---|
| NEMA 3 | 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); and that will be undamaged by the external formation of ice on the enclosure. | 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 (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 additional level of protection against corrosion; and that will be undamaged by the external formation of ice on the enclosure. |
| NEMA 3X | 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; to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (rain, sleet, snow); that provides an additional level of protection against corrosion; and that will be undamaged by the external formation of ice on the enclosure. | — |
| NEMA 3R* | 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 provide 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. | 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 (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 additional level of protection against corrosion; and that will be undamaged by the external formation of ice on the enclosure. |
| NEMA 3RX* | Same protection as NEMA 3R, but with added protection against corrosion. | — |
| NEMA 3S | Same as NEMA 3, except that external operating mechanisms remain operable when ice laden. | Same as NEMA 3X, except that external operating mechanisms remain operable when ice laden. |
| NEMA 3SX | Combination of 3X corrosion protection and 3S ice-operable mechanisms. | — |
| NEMA 4 | Same as NEMA 3R, plus protection against splashing and hose-directed water. | Same as NEMA 3RX, plus protection against splashing and hose-directed water. |
| NEMA 4X | Same as NEMA 4, with additional corrosion protection. | Same as NEMA 4, with additional corrosion protection. |
| NEMA 6 | Same as NEMA 4, plus protection against occasional temporary submersion. | Same as NEMA 4X, plus protection against occasional temporary submersion. |
| NEMA 6P | Same as NEMA 6, with additional corrosion protection. | Same as NEMA 6, with additional corrosion protection. |
Table 1
From NEMA 250-2003
*These enclosures may be ventilated.
Understand the right protection of NEMA types and applications’ location could save you time and cost of your project, contact Nemaco team to find the right solution for NEMA enclosures for outdoor nonhazardous locations.
