NEMA Ratings, Applications and Recommendations for Industrial Facilities

Monitoring standards of electrical components in industrial sectors is a salient part of ensuring safety during operations. Without such standards, workers would be open to unpredictable risks related to equipment failure or malfunction. For heavy-duty enclosures, the National Electrical Manufacturers Association (NEMA) sets forth a unique classification system that establishes and defines the performance of such components.

It is important to note that NEMA does not test industrial products. However, regulatory testing authorities, such as Underwriters Laboratories (UL) and the Canadian Standards Association

(CSA) use NEMA ratings as investigative guidelines during inspection and listing of enclosures.

NEMA Enclosure Definitions

Below is a list of NEMA types and their corresponding definitions:

  • Type 1: General purpose and indoor use; protection from dust, light and splashing (not dust tight)
  • Type 2: Drip tight (consists of drip-shielding components)
  • Type 3: Weather resistant; protection from falling dirt, windblown dust and formation of ice
  • ­Type 3R: Same as Type 3; no protection from windblown dust
  • Type 3S: Same as Type 3; useable under thick formations of ice
  • Type 3X, 3RX, 3SX: Same as their respective Types, with additional corrosion protection
  • Type 4, 4X: Water tight; “X” refers to additional corrosion protection
  • Type 5: Dust tight
  • Type 6, 6P: Submersible in oil or water (temporary); “P” refers to occasional, prolonged submersion (not continuous submersion)
  • Type 7: For use in Class I, Groups A, B, C, D hazardous locations (indoor)
  • Type 8: Same as Type 7, but for both indoor and outdoor use
  • Type 9: For use in Class II, Groups E, F, G (indoor and outdoor use)
  • Type 10: Addresses MSHA requirements, 30 CFR Part 18 (1978)
  • Type 11: General applications; protection from corrosion related to liquids/gases
  • Type 12, 12K: General applications (indoor use); protection from dust, falling dirt and dripping liquids (non-corrosive)
  • Type 13: General applications; protection from dust, water spraying and coolants (non-corrosive)

Applications in Industrial Environments

The type of NEMA enclosure dictates how the unit will be applied in industrial settings. For example, since Type 1 does not offer extensive protection from dust, water, contact and corrosion, the enclosure is only usable indoors, under non-classified, normal conditions. All NEMA ratings ending with an “X” is applicable in marine sectors and industrial facilities that are exposed to corrosive agents during wash-down sessions, including food processing plants and wastewater facilities (note: application of NEMA-rated products in hazardous locations must adhere to their explosion proof classifications, dictated by NFPA standards/NEC).

Although rare, NEMA ratings can be applied to mobile devices and other mainstream products with enclosure components. As a general rule, NEMA 4 ratings or higher are used comprehensively to address rough elements in outdoor environments. Though it would be possible to use NEMA 3-rated enclosures in outdoor settings as well, based on their respective definitions. NEMA 7, 8 and 9 are intended for use in hazardous locations and confined spaces.

NEMA Ratings vs IP Ratings

When talking about NEMA guidelines, Ingress Protection definitions are often referenced. This is because both are used to rate protection of industrial equipment and enclosures. However, it is important to consider that the rating systems vary greatly in the way they are applied. For instance, NEMA standards are mostly used in the US and Canada, while IP ratings are applicable worldwide. Furthermore, IP definitions are limited, in a sense that the system only covers the ingress of water and/or solid objects. NEMA extends this scope by rating corrosion resistance and explosive atmospheres.

Interestingly, because the two rating systems offer similarities in their definitions, some NEMA ratings actually have an IP rating equivalent:

  • IP10 = NEMA 1 (indoor use, protection from falling dirt)
  • IP11 = NEMA 2 (indoor use, protection from falling dirt and water)
  • IP54 = NEMA 3 and NEMA 3S (outdoor use, protection from windblown dust, rain, sleet and ice formation)
  • IP14 = NEMA 3R (outdoor use, protection from rain, sleet and ice formation)
  • IP56 = NEMA 4X (protection from corrosion, windblown dust, rain, splashing water and ice formation)
  • IP52 = NEMA 12 and 12K (indoor use, protection from dust, dirt and dripping (non-corrosive liquids)
  • IP54 = NEMA 13 (indoor use, protection from dust, spraying water, oil and non-corrosive liquids)

There is no IP equivalent to NEMA 7, 8, 9, 10 and 11. In application, you should not attempt to replace NEMA protection with IP protection and vice versa. Although some offer the same level of protection, the way they are defined by the regulating authority should still be taken into consideration. For example, based on the list above, IP56 should offer a certain level of protection from corrosion, since it is equivalent to NEMA 4X. But a closer look at the definition of IP56 suggests that protection from corrosion is not available (as mentioned earlier, IP rating systems do not include corrosion resistance). Using the same example, if you wanted to use a NEMA 4X enclosure during (low pressure) wash-down sessions, it would be possible to reference IP56 as the equivalent, since both offer the same level of water protection.

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