Everything you've wanted to know about NEMA

Different ratings provide, for example, differing levels of protections from fire, chemicals, water, corrosive materials, ingress and even personell.

Here's what you're about to learn:

  • What NEMA stands for
  • How long NEMA has been around
  • How many different NEMA types there are
  • The different NEMA ratings and what they mean
  • The best way to make sure you get the best quote for your enclosure

I'm sure you're at least familiar with what NEMA means, or have at least some idea, of what it means when it comes to enclosures. At it's most basic level, when it comes to enclosures anyways, the NEMA rating represents different levels of protection against environmental elements, chemicals, corrosive materials, and more.

The acronym 'NEMA' stands for National Electrical Manufacturers Association. NEMA actually covers a much broader category that expands far beyond just electrical enclosures. The NEMA association has published over 700 standards, technical papers, and application guides that set the standard for everything from how to safely distribute and control electricity in a building to addressing new technology and it's applications.

The NEMA association serves seven major markets and industries:

  1. Building Systems
  2. Building Infrastructure
  3. Lighting Systems
  4. Industrial Products & Systems
  5. Utility Products & Systems
  6. Transportation Systems
  7. Medical Imaging

The National electrical manufacturers association was started in 1926, which was a year after roughly half of the homes in the United States had electricity. The published standards provided by NEMA provides information for improving safety and mitigating risk while promoting product interoperability in order to stregthen demand.

The NEMA association is also a community that you can join. In order to gain NEMA membership you need to be an enterprise that's actively engaged in the manufacturing of any electrical product that is developed and design for sale in the United States, it's sold commercially in the U.S, and it's within the scope of NEMA products.

NEMA membership has many benefits which you can investigate further at the official NEMA website. If you would just like to view the application to become a member you can view the pdf file here.

NEMA is always posting new articles so feel free to check out their page and browse for a while.

There are six NEMA standards by which electrical enclosures can be manufacturerd:


NEMA 1 electrical enclosure box

Use case: Indoor

These provide some amount of protection to individuals when it comes to accessing parts that may be hazardous to an individual. NEMA 1 provides the minimum amount of protection that may be required. They provide the equipment inside protection against solid foreign objects such as dirt.


NEMA 3 electrical enclosure box

Use case: Both indoor and outdoor

NEMA 3 in an indoor or outdoor enclosure that provides protection a step above the NEMA 1. It provides protection against, not only falling dirt, but also windblown dust. It also provides protection against equipment damage due to ingress of water such as snow, rain, or sleet (does not protect against submerssion) and it also protects the equipment inside against external formation of ice.


NEMA 3R electrical enclosure box

Use case: Both indoor and outdoor

The NEMA 3R is also an enclosure that can be used in either outdoor or indoor situations. Some of the characteristics of the NEMA 3R are that they protect against accidental contact with enclosed equipment, protection from falling dirt,rain,sleet and/or snow, drainage provision, protection against rain at a level higher than the lowest live part, and alternat locking and latching mechanism.


NEMA 4 electrical enclosure box

Use Case: Both indoor and outdoor

NEMA 4 provides protection inside against falling dirt and windblown dust. It also provides a decent amount of protection again water (splashing water, and hose directed water, rain, sleet, snow). In addition to significatn protection against water it also protects against external ice.


NEMA 4X electrical enclosure box

Use case: Indoor and Outdoor

This enclosure provides an added layer of protection against corrosion. The NEMA 4s provides a decent amount of protection against water. It protects against host directed water, splashing water, rain, sleet, and snow.

NEMA 12:

NEMA 12 electrical enclosure box

Use case: Indoor (constructed without knockouts)

Provide some protection to individuals against accessing hazardous parts. They also provide some protection from falling dirt, dust, lint, and fibers.  NEMA 12 enclosures however do not provide a lot of protection against water. They protect against very light splashing or dripping water, but can't protect heavy rain, or submerssion.

These are the rating types according to the official NEMA website. But there are actually twenty different rating types that aren't directly listed here, but you can find more information on all the NEMA ratings on the official NEMA website.

If you're more the type of person that likes to see your information visually so you can easilly determine what type of NEMA enclosure fits your needs best we've provided you with a

If you're of the visual type, we've we've pulled this table from the NEMA pdf that's included in our information package for your easy reference.

At a Glance:

Table from NEMA PDF that compares each NEMA rating

If you'd like to download the full NEMA rating PDF feel free to get it here.

If you have any questions or need to request a quote for a custom made NEMA enclosure or electrical enclosure do not hesitate to contact us.

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