What Is A NEMA Rating?

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The NEMA rating system was created by the United States National Electrical Manufacturers Association and rates the degree of protection against corrosion, gasket aging and construction practices against designated environmental conditions. In our case, we’re referring to NEMA ratings for outdoor aluminum enclosures intended to be used for DVR’s, PoE network switches, CCTV fiber modems and more. Anything above a 4 (4, 4X) is for fully submersible applications such as in a marine environment, or hazardous materials such as at a Government or Nuclear facility.

The most common ratings for outdoor enclosures in the data and security field are:

NEMA 3, 3R, 3S, 3X

Weather-resistant. Protects against weather hazards such as rain & sleet. Used outdoors on ship docks, in construction work, tunnels & subways. 3X includes corrosion.


Watertight. Must exclude at least 65 GPM of water from 1″ nozzle delivered from a distance no less that 10 ft. for 5 minutes. Used outdoors on ship docks, in dairies and in breweries. The 4X model has corrosion resistance.

Why NEMA Ratings Matter

When installing sensitive and expensive electronic equipment outdoors it is best to install items such as network switches in NEMA rated enclosures that will protect your expensive products from the elements. When choosing the right enclosure be sure to take into consideration the enclosure material type (aluminum, stainless steel or plastic) as well as the surrounding environment in 360 degrees.

For example, if your project consists of installing equipment around sprinklers, be sure to purchase a NEMA 4 rated enclosure as opposed to a regular NEMA 3 outdoor box; NEMA 4 enclosures are completely weatherproof while a NEMA 3 enclosure only protects from rainfall, not water from the ground.

It is important to note that while there are nationally recognized standards, there are not currently any national certifications or independent testing done on individual products such as is done for UL Listings. According to NEMA “everyone is permitted to identify self-certified products as NEMA 4, or NEMA 3R, etc. to signify a particular classification of product both on the product and within literature.” When choosing your outdoor NEMA enclosure supplier you should ask them about what tests they have run on their products to ensure that the products meet the voluntary rating standards. Download NEMA FAQs: Enclosures for more information.

Call us today at (904) 674-2976 for more information. ArmorLogix is a proud provider of NEMA enclosures.

Sources: Visit the NEMA Website for a full list of NEMA enclosure types.Reference: Wikipedia, http://en.wikipedia.org/wiki/NEMA_enclosure_types

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