Electrical Enclosure Standards: NEMA and IP Ratings

Electrical enclosures

Electrical enclosures are rigid, protective structures that are installed in electrical circuits and contain switches, buttons, connections, knobs, or displays. These structures provide a layer of protection to the circuit as well as to the electrical components contained within them; they also allow operators to interact with the system via switches, buttons, or other controls while protecting them against the risk of electrical shock.

Electrical enclosures are rated according to their ability to encourage the release of excessive heat, to insulate the circuit and its components from electromagnetic interference, or simply to protect against the elements.

Just what electrical enclosure is most suitable for a given circumstance, however, is subject to its categorization according to certain systems, of which the two most widespread are the IP and NEMA standards.

NEMA: Setting Standards for Electrical Enclosures

In the United States, there is an organization known as the National Electrical Manufacturers Association that sets the standards for electrical enclosures, which are referred to as the NEMA Enclosure Type Standards.

NEMA’s protection rating system is used to categorize electrical enclosures according to the degree of protection they offer the components within them. Some of the most popular types of NEMA standards are as follows:

  • NEMA 1: Basic indoor protection, guarding internal components against accidental contact; also protects against falling dirt and dust.
  • NEMA 2: Also basic indoor protection against contact and settling dust and dirt, but with added protection against falling or dripping water.
  • NEMA 3: Basic outdoor protection against the elements. NEMA 3 type enclosures are protected against dirt, dust, and precipitation, including rain as well as snow and ice.
  • NEMA 4: Offers the same protection as NEMA 3 series rated enclosures, but with additional protection against falling or splashing water. A special type of NEMA 4 type enclosure is known as a NEMA 4X, which is also resistant to harsh chemicals, corrosion, and saltwater.
  • NEMA 5: Basic indoor protection, similar to NEMA 1 and NEMA 2 ratings, but with additional protection against airborne debris.
  • NEMA 6: Provides robust protection for outdoor applications against a wide range of elements, including dirt, dust, ice, and snow. However, NEMA 6 enclosures are also rated to protect against temporary submersion. A special type of NEMA type rating is NEMA 6P, which protects against prolonged submersion.
  • NEMA 7, 8, 9, and 10: NEMA 7-10 series ratings are unique in that they protect against specific hazardous conditions such as fire and explosions.
  • NEMA 12: NEMA 12 series electrical enclosures provide basic indoor protection against settling dust and offer ingress protection against certain non-corrosive liquids, such as oil and coolant. A special type of NEMA rating is NEMA 12K, which offers the same protection as other NEMA 12 enclosures, but contains prefabricated knockouts. NEMA 12 series enclosures are popular not only for the level of protection they offer but for their generally affordable cost.

As you can see, a higher rating does not necessarily mean a higher level of protection. It is important to evaluate NEMA ratings on a case-by-case basis as the unique features are specific to each categorization.

In addition to the NEMA ratings, some manufacturers use a separate rating, known as the IP, or Ingress Protection Rating.

Electrical enclosures

IP Rating

Ingress Protection, or IP, ratings, have been formulated according to an international standard and are used to categorize electrical enclosures according to their resistance to ingress of solids and liquids.

The IP system uses a code that follows the “IPXX” format, wherein the first “X” is a number that represents protection against solids such as dust and the second “X” connotes protection against liquids.

Protection against solids (first X):

  • 0: No protection.
  • 1: Protection against objects larger than 50mm.
  • 2: Protection against objects as small as 12mm.
  • 3: Protection against objects as small as 2.5mm.
  • 4: Protection against objects as small as 1mm.
  • 5: Protection against limited amounts of dust.
  • 6: Complete protection against dust, no dust ingress permitted.

Protection against liquids (second X):

  • 0: No protection against water or other liquids.
  • Minor protection against light dripping water.
  • Protection against water dripping from an angle of up to 15°.
  • Protection against water dripping from an angle of up to 60°.
  • Protection against water splashing from any direction.
  • 5: Protection against pressurized jets of water from any direction.
  • 6: Protection against temporary flooding.
  • 7: Protection against temporary immersion of up to 1 meter.
  • 8: Sustained protection against immersion of greater than 1 meter for prolonged periods of time.
Electrical enclosures

Since two numbers must be combined to give a cogent reading, an IP rating might read as IP67 (like some of the aluminum junction boxes we offer here). A rating of IP67 offers complete protection from dust and particulate solids, as well as protection against temporary immersion in water of up to 1 meter of depth.

Electrical Enclosure Materials: Aluminum and Polymer (ABS Plastic)

Not all electrical enclosures are made from the same material, and in fact, the material used in construction can support a higher level of protection for the components inside. These mounts and enclosures are often made of metals including stainless steel, aluminum, fiberglass, polycarbonate, polymers, and ABS plastic.

Here we offer electrical enclosures, including junction boxes, terminal enclosures, and button boxes, made from aluminum and ABS plastic, in a wide range of colors and sizes.

Be aware that the material of the electrical enclosure will affect not only its cost but also its protection rating. For example, some of our ABS plastic enclosures are made with molded knockouts that facilitate the installation of wires; they are also more affordable than our aluminum electrical enclosures.

However, our aluminum enclosures are extremely durable and powder-coated to provide a higher degree of protection against corrosion. Our aluminum enclosures are also IP67 rated, to provide superior protection against ingress of water, dust, and other particulate matter.

Contact Us to Learn More!

Do you have additional questions regarding the specific needs of your unique circumstances? Don’t try to decipher all these codes on your own - get in touch with us and we’ll be glad to help ensure you choose the electrical enclosures that are perfectly suited for your needs.

Feel free to reach out to us at 800-966-2345 for additional information.

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