NEMA Enclosures Ratings Gudie

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NEMA Ratings For Enclosures

The National Electrical Manufacturers Association (NEMA) develops North American standards for several kinds of electrical enclosures used in industrial applications. Each is certified to guard against people's access to hazardous parts as well as type-specific designated environmental conditions. A standard NEMA enclosure may be certified to protect against environmental dangers such as water, dust, oil, or coolant, as well as corrosive atmospheres including acetylene or gasoline. 

NEMA Enclosure Types PDF
NEMA Ratings For Enclosures

NEMA Enclosure Types

Some of the basic types of electrical enclosures that you’ll find on the market today include:

Some of these enclosure types may overlap with others, such as outdoor enclosures that are both waterproof and dustproof. However, in order to make an appropriate assessment of an enclosure's protective properties, you need be aware with NEMA enclosure ratings and other rating systems that provide a standard for an enclosure's level of protection.

NEMA Ratings and Other Enclosure Standards

When it comes to electrical enclosure standards, there are several alternatives available to the electrical engineering and manufacturing industries. Several industry groups and organizations assist educate and protect customers by establishing standards for the production and usage of electrical components.

When it comes to commercial and industrial applications, two organizations spring to mind: the International Electrotechnical Commission (IEC) and the National Electrical Manufacturers Association (NEMA). These two organizations are related with the Ingress Protection (IP) rating system and the NEMA rating scale.

The IEC services the world's manufacturers, whereas NEMA serves the US. It's also crucial to understand Underwriters Laboratories (UL) ratings. A UL rating is essentially an IP or NEMA rating that has been evaluated and validated by UL's independent safety experts to meet the applicable criteria.

Nema Enclosure Ratings Chart​

To choose the right enclosure, you must understand NEMA ratings. Some grades, such as NEMA 12 vs. NEMA 4, have significant variances that will affect whether your enclosure sufficiently protects its encased item. The following NEMA 250-2003 codes cover non-hazardous applications, enclosure types, applications, and environmental conditions they protect against when correctly installed:

NEMA 1 Rating: 

NEMA 1 enclosures are the most basic type of NEMA rated protection.

  • For indoor use only.
  • Solid Ingress Protection: Accidental contact, falling dirt
  • Water Ingress Protection: None
  • Other Protective Qualities: None

NEMA 2 Rating: 

NEMA 2 enclosures are a step up from NEMA 1 enclosures that include limited water ingress protection.

  • For indoor use only.
  • Solid Ingress Protection: Accidental contact, falling dirt
  • Water Ingress Protection: Dripping, minor splashing
  • Other Protective Qualities: None

NEMA 3 Rating: 

NEMA 3 enclosures are the most basic type of outdoor enclosures and provide solid protection for non-hazardous outdoor environments.

  • Indoor/Outdoor: Either
  • Solid Ingress Protection: Accidental contact, falling dirt, windblown dust
  • Water Ingress Protection: Rain, sleet, snow
  • Other Protective Qualities: External ice formation
  • NEMA 3 enclosures are found on construction sites, ship docks, and in tunnels and subways subject to wet conditions.

NEMA 3R Rating: 

NEMA 3R enclosures are similar to Type 3, but provide slightly less protection against windblown dust. (See our article on NEMA 3 gegenüber NEMA 3R.)

  • Indoor/Outdoor: Either
  • Solid Ingress Protection: Accidental contact, falling dirt
  • Water Ingress Protection: Rain, sleet, snow
  • Other Protective Qualities: External ice formation

NEMA 4 Rating: 

NEMA 4 enclosures are strong outdoor enclosures suitable for a wide variety of outdoor and indoor applications.(See our article on NEMA 3 vs. NEMA 4.)

  • Indoor/Outdoor: Either
  • Solid Ingress Protection: Falling dirt, windblown dust
  • Water Ingress Protection: Rain, snow, sleet, splashing water, hose spray
  • Other Protective Qualities: External ice formation

NEMA 4X Rating: 

NEMA 4X enclosures are similar to Type 4, but include additional protection against corrosion.

  • Indoor/Outdoor: Either
  • Solid Ingress Protection: Windblown dust
  • Water Ingress Protection: Rain, snow, sleet, splashing water, hose spray
  • Other Protective Qualities: Corrosion, external ice formation

NEMA 5 Rating: 

NEMA 5 enclosures are designed for indoor use to protect against a wide variety of airborne particulates and light water ingress. it has less protection than NEMA 4.

  • Indoor/Outdoor: Indoor
  • Solid Ingress Protection: Falling dirt, settling airborne dust, lint, fibers, flyings
  • Water Ingress Protection: Dripping, minor splashing
  • Other Protective Qualities: None

NEMA 6 Rating: 

NEMA 6 enclosures are designed for tough outdoor applications that require high-performance waterproof enclosures.

  • Indoor/Outdoor: Either
  • Solid Ingress Protection: Falling dirt
  • Water Ingress Protection: Hose spray, temporary submersion at limited depth
  • Other Protective Qualities: External ice formation

NEMA 12 Rating: 

NEMA 12 enclosures are indoor enclosures designed for general use with a greater degree of protection than Type 1 or Type 2.

  • Indoor/Outdoor: Indoor
  • Solid Ingress Protection: Falling dirt, circulating dust, lint, fibers, flyings
  • Water Ingress Protection: Dripping, minor splashing
  • Other Protective Qualities: None
  • It is similar to NEMA 3, but it is for indoor use, so instead of protecting against windblown dust it protects against settling airborne dust, lint, and fibers.
  • Despite the large number, it is a basic level of protection. It may be helpful to think of it as NEMA 1.2 rather than NEMA 12.

NEMA 13 Rating: 

NEMA 13 enclosures are similar to Type 12, but include additional protection against oil and coolant seepage.

  • Indoor/Outdoor: Indoor
  • Solid Ingress Protection: Falling dirt, circulating dust, lint, fibers, flyings
  • Water Ingress Protection: Dripping, minor splashing
  • Other Protective Qualities: Oil and coolant seepage (non-corrosive)

NEMA-Rating vs. IP Rating

NEMA and IP ratings both describe degrees of protection against substances such as water and dust, but they employ distinct test techniques and specifications to determine enclosure types, with NEMA using NEMA 250 and IP using IEC standard 60529.

The NEMA rating system, like the IP rating system, helps us to identify enclosures that are appropriate for the environment in which they will be deployed.

NEMA ratings are only used for enclosures, but IP ratings can be used for any type of equipment.

Lesen Sie mehr: NEMA vs. IP-Bewertungen: Was ist der Unterschied?

NEMA Rating Chart