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As e-commerce grows, the globe shrinks and industrial products will continue to cross borders more readily.

We feel like it’s our duty to shed some light onto what all those pesky enclosure ratings mean and why there are so many!

Let’s start on the national level with NEMA (National Electrical Manufacturers Association).

In the mid-1920’s, as the electrical innovation world was quickly becoming the Wild West, it became apparent that regulations and standardization was necessary. Enter in NEMA, a collection of separate manufacturers and trade associations who have since established performance benchmarks for a variety of electrical apparatuses. In industrial applications, NEMA is generally synonymous with enclosure ratings, which is how we will be discussing them moving forward.

Here are some of the more prevalent NEMA ratings we tend to see:

It’s important to mention that NEMA does not actually test the products they rate; it’s more of a handy guide for understanding how much protection your enclosure will have.

There is, however, an international association that DOES test or provides testing platforms for whatever they rate….any guess who they are or what their rating is? Ok, we are not going to actually make you guess, it is the International Electrotechnical Commission (IEC).

Feel like reading all the official NEMA enclosure ratings? Check them out below!

Similarly to NEMA, IEC was created to make sense of the influx of electrical innovations, and since 1904 they have worked to maintain a uniform and cooperative system of standardization globally.

As enclosures made their way to the international market, a system for protection ratings needed to be set in place. Hello IP (Ingress Protection) ratings! These ratings, which the IEC actually tests, are used to classify the degree of protection that an electrical enclosure provides from solid objects and liquids.

According to the IEC, standards for defining the degrees of protection are based upon the following capabilities:

  1. Protection of persons against access to hazardous parts inside the enclosure
  2. Protection of the equipment inside the enclosure against ingress of solid foreign objects
  3. Protection of the equipment inside the enclosure against harmful effects due to the ingress of water.

What does that even mean?!? Simply put, can a body part, dust/dirt, or water get inside the enclosure?

To further clarify, the IEC expressed that IP ratings are rated based on protection from all of these potential scenarios:

  • mechanical impacts
  • corrosion
  • corrosive solvents (for example, cutting liquids)
  • fungus
  • vermin
  • solar radiation
  • icing
  • moisture (for example, produced by condensation)
  • explosive atmospheres
  • The protection against contact with hazardous moving parts external to the enclosure (such as fans…”

Did you know?

IP ratings are also limited to the enclosures of electrical equipment with a rated voltage not exceeding 72.5 kV.

It might be important to note that these ratings have nothing to do with electrical protection classes and will not help when determining the prevention of electrical shock.

So, now that we know ALL the background behind IP ratings, what do the numbers actually stand for? The first number signifies the protection against solid objects; the second number tells you the degree of protection against liquids.

First Digit: Solids

  • 0:  not protected
  • 1: >50mm (example; larger body parts, back of hand)
  • 2: >12.5mm (example: fingers are safe!)
  • 3: >2.5mm (example: thick wire)
  • 4: >1mm (example: screws, thinner wire)
  • 5: Dust protected (not completely protected from dust but shouldn’t let too much in if dust isn’t overwhelming)
  • 6: Dust tight (no dust is getting in here!)

Second Digit: Liquids

  • 0: not protected
  • 1: Dripping water
  • 2: Dripping water when tilted up to 15°
  • 3: Spraying water
  • 4: Splashing water
  • 5: Water jets
  • 6: Powerful water jets (what defines powerful? 12.5mm nozzle)

Generally there is agreement for this cross reference:

NEMA 1 IP23
NEMA 3R IP32
NEMA 4 IP66
NEMA 4X IP66
NEMA 12 IP55
NEMA 13 IP65

Way to go! You’re now so much smarter when it comes to what each of these ratings mean and their history…GREAT! How does this help you buy an enclosure from Germany if you’re in America and only know you need a NEMA 4X? We’ve got you covered, sorta…

We want to be clear; technically, there is not a direct conversion between NEMA and IP ratings. There is a generally accepted comparison and most of the time, NEMA ratings will meet or exceed the IP ratings. However, this does not mean an IP rating will meet all of the NEMA criteria, it’s best to double check all your requirements before ordering.

Other rating standards that may pop up:

  • International Organization for Standards (ISO): “ISO is an independent, non-governmental international organization with a membership of 162 national standards bodies” that have published over 22,000 standards and documents ranging from food and health safety to packaging equipment and facility management.
  • (CE) Conformité Européene/”European Conformity”: the product complies with the essential requirements of the relevant European health, safety and environmental protection legislation
  • Underwriters’ Electrical Bureau (UL): Established in 1894 during the Chicago World’s Fair. Involved in writing standards for electrical components, building products, fire safety standards, industrial control equipment, plastic material, wire, cable, and even mobile phones among many other things we deal with on a day to day basis.
  • Canadian Standards Association (CSA): Originally founded in 1919 as the Canadian Engineering Standards Association (CESA). CSA exists to develop standards specializing in climate change, business management and safety and performance standards, including those for electrical and electronic equipment, industrial equipment, boilers and pressure vessels, compressed gas handling appliances, environmental protection, and construction materials.

Keep us in mind the next time you need anything with an IP or NEMA rating. We have a full offering of enclosures, drives, motors and industrial components! Our MWA in-house tech support is always available to help you find the best product for your application.

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Visual thinker in a digital spectrum, or in layman’s terms….I make all the visual content for Marshall Wolf Automation 🙂 With a background in video advertisement and film production, I work with MWA’s marketing department to keep our customers reading our blogs and viewing our products.

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