A Complete Guide to NEMA Enclosure Ratings

NEMA ratings can help clarify whether an enclosure is suitable for a specific environment that you plan to purpose it for. The National Electrical Manufacturers Association (NEMA) is an organization developed to form the technical standards for the manufacturing of electrical and medical imaging equipment. Aiming to set national standards for our industry, NEMA has developed guidelines for enclosures that must comply with certain safety standards and specific environmental properties. In this guide, Power Assemblies will review the differences between our most common NEMA enclosures, which in hand will explain the environmental properties each enclosure is protected against. If you’re unsure which NEMA rating you need for a job, this blog will help you clarify which enclosure is most suitable and where it should be purposed for the most optimal use.

NEMA 1

Type 1 NEMA rated enclosures are suitable for indoor use only and provide a means of protection from unauthorized personnel gaining access to equipment inside the enclosure along with protection against certain falling objects such as dirt or dust. All Power Assemblies standard products are rated NEMA3R for outdoor use, however, our enclosures are also suitable for indoor use with added protection. If you’re interested in a NEMA 1 Power Assemblies enclosure, you can contact our engineering team for custom projects at (866)-825-8525.

NEMA 2

Type 2 NEMA rated enclosures include the same level of protection as Type 1, while also including an added protection against light water from affecting equipment inside the enclosure. Examples of light water include protection from light splashing or possible water dripping inside the building.

NEMA 3

Type 3 NEMA rated enclosures are ideal for indoor or outdoor use and provide a means of protection against unauthorized person gaining access to hazardous parts or equipment inside of the enclosure. These enclosures include protection against falling objects such as dirt or windblown dust and provide a degree of protection with respect to harmful effects on equipment inside the enclosure. This includes protection against the possible entrance of water such as rain, sleet, or snow.

NEMA 3R

Type 3R NEMA rated enclosures include the same level of protection as TYPE 3, while also including an added benefit of protection allowing equipment to remain operable when ice is formed on the exterior of the enclosure. Many of Power Assemblies Products come standard as NEMA 3R rated. Some of our most common power distribution equipment associated with this level of protection include our Camlock Connection Box (CCB), Generator Docking Station (GDS), Load Banking Station (LBS), and our custom Spider boxes along with many more of our innovative power solutions, which you can find under the Power Distribution section on our website.

NEMA 3RX

Type 3RX NEMA rated enclosures are very similar to those of NEMA 3R and include the same level of protection with the included benefit of protection against corrosion. This corrosion-resistant enclosure is suitable for both indoor and outdoor use in environments that are exposed to harsh chemicals, gases, or corrosive materials.

NEMA 4/4X

Type NEMA 4 and 4X rated enclosures offer the same level of protection as that of NEMA 3 enclosures. It is suitable for indoor or outdoor use and offers a degree of protection against unauthorized personnel gaining access to the cabinet. These enclosures protect against solid foreign objects such as dirt and windblown dust. The main difference between NEMA 3 and 4 is that NEMA 4 will protect against rain, sleet, snow, splashing water, along with hose-directed water. 

This means that if you wanted to wash down your NEMA 4 enclosure, you would not need to worry about damaging the components inside. Both NEMA 4 and 4X protect the components inside against ice buildup on the exterior of the enclosure. NEMA 4X offers an additional level of protection against corrosive materials, like that of NEMA 3RX.

NEMA 5

Type 5 Rated NEMA enclosures are similar to the level protection of NEMA 4 enclosures but are only suitable for use indoors. These enclosures can protect against light splashing but cannot be submerged for periods of time by heavy rain, sleet, or snow. 

NEMA 12/12K

Type 12 NEMA enclosures are intended for indoor use only. They offer a degree of protection against unauthorized personnel gaining access to inside materials. These enclosures also offer protection against dripping and or splashing water and are rust-resistant. NEMA 12K enclosures are equipped with existing knockouts for use with conduit, cables, or connectors.

NEMA 12/4

Lastly, our NEMA 12/4 enclosures are rated for indoor or outdoor use and will protect your equipment from dirt, windblown dust, and various splashing waters. This includes rain, sleet, snow, splashing water, and hose-directed water. The “12/4” rating indicates that these enclosures offer features from both NEMA 4 and 12 in one single enclosure. 

For questions regarding any specific NEMA ratings, stainless steel corrosion-resistant enclosures, or any Power Assemblies products, you can contact our engineering team directly at (866)-825-8525 or email us at Sales@PowerAssemblies.com