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NEMA Ratings - The complete Guide for Beginners

In this article, you will learn about NEMA Ratings, and how they are related to IP Ratings.

In this article, we are going to learn about NEMA Ratings, and how they are related to IP Ratings.

NEMA is an American standard and IP is a European standard.

You might have come across one of our earlier articles about IP ratings. If you haven’t, it would be good to check that article.

What is a NEMA Rating?

NEMA stands for National Electrical Manufacturers Association and is an organization developed to form the technical standards for the manufacturing of electrical equipment and medical imaging equipment.

NEMA works to set industry standards for safety, innovation, interoperability, environment, and market enhancement of our industry.

Although the NEMA organization oversees a variety of responsibilities in the electrical manufacturing industry, they are most closely associated with the term NEMA Ratings and the type of enclosure an electrical component is built with.

NEMA-Rating vs. IP Rating

This is where the similarities with IP ratings begin. IP stands for International Protection but is almost always interpreted as Ingress Protection because it is the rating system that denotes the level of protection from ingress of dust and water.

NEMA ratings and IP ratings both define degrees of protection against substances such as water and dust but use different test methods and parameters to define their enclosure types, with NEMA using NEMA 250 and IP using IEC standard 60529.

The NEMA rating system, just like the IP rating system, allows us to identify an enclosure to suit the environment that it is to be installed.

NEMA ratings are used exclusively for enclosures, but IP ratings can be used for all kinds of devices.

The IP rating systems use two digits, for example, IP66, where the first number indicates the level of dust protection. In this case, the 6 means the enclosure is completely protected against dust.

The second number indicates the level of water ingress protection, with 6 meaning the enclosure is protected against heavy water jet spray.

There is no direct conversion between IP ratings and NEMA ratings, however, the level of protection they provide is comparable, so we can say that the NEMA rating equivalent of IP66 is NEMA 4 or 4X, with the 4X providing an additional level of protection against corrosion.

Let’s take a look at the different levels of NEMA rating.

Types of NEMA Enclosures

Let’s take a look at the different levels of NEMA rating.

NEMA ratings for non-hazardous locations go from 1 through to 6, and 11 through to 13.

NEMA ratings for hazardous locations go from 7 through to 10.

  1. NEMA Types for Non-Hazardous Area

Type 1 NEMA

Type 1 NEMA rated enclosures are constructed for indoor use to provide a degree of protection against access to hazardous parts and to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects, for example, falling dirt.

Type 2 NEMA

Type 2 NEMA rated enclosures offer the same level of protection as a Type 1, but with added protection to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water, for example, dripping or light splashing.

Type 3R/3RX NEMA

This is now where things get a bit different. Type 3 NEMA ratings are broken down into 3 protection levels, with a corrosive protection option, so 6 in total.

Type 3R and 3RX NEMA rated enclosures are engineered for indoor or outdoor use and protect against rain, sleet, snow, dirt, and prevents the formation of ice on its enclosure, with the 3RX adding protection against corrosion.

Type 3/3X NEMA

Type 3 and 3X NEMA rated enclosures are rain-tight, sleet-tight, and dust-tight and are made for both indoor and outdoor use.

NEMA 3 and 3X designates added protection against dust beyond a NEMA 3R or 3RX enclosure, again with the 3X adding protection against corrosion.

Type 3S/3SX NEMA

Type 3S and 3SX NEMA rated enclosures benefit from the same protection as a NEMA 3, however, provides protection when ice forms on the enclosure and will remain operable when covered in ice, again with the 3SX adding protection against corrosion.

Type 4/4X NEMA

Type 4 and 4X NEMA rated enclosures are intended for indoor or outdoor use and provide the same protections as a NEMA 3 enclosure with additional protection against water ingress and/or hose-directed water. So, if you need to clean off your NEMA 4 enclosure, you don’t have to worry about water damaging your electrical components.

Type 5 NEMA

A Type 5 rated NEMA enclosure offers a similar level of protection as a NEMA 4 enclosure but is intended that its primary use be indoors. It can handle light splashing, but cannot be submerged for periods of time.

Type 6/6P NEMA

A Type 6 rated NEMA enclosure offers the same protection as a NEMA 4 enclosure, with added protection from temporary water submersion up to a designated depth.

A 6P enclosure means the enclosure can be submerged for a prolonged period of time.

Type 11 NEMA

Type 11 NEMA enclosures are corrosion resistant and offer protection whilst submerged in oil. They are intended for use indoors to protect the equipment against dripping of corrosive liquids.

Type 11 also protects against the corrosive effects of fumes and gases by providing immersion protection of the equipment in oil.

Type 12 NEMA

Type 12 and 12K NEMA enclosures are intended for general-purpose, indoor use.

The NEMA 12 and 12K enclosures protect against dripping and splashing water, are rust-resistant. A type 12 does not include knockouts, which are partially punched openings that can be removed to accommodate cables, connectors or conduits, whereas a Type 12K does.

Type 13 NEMA

Finally, Type 13 NEMA enclosures are for general purpose indoor use. They provide the same protection as the NEMA 12 enclosures, but with added protection against dripping and/or sprayed oils and coolants.

2. NEMA Types for Hazardous Area

Type 7 NEMA

Type 7 NEMA enclosures are built for hazardous locations, so the enclosure is explosion-proof and made for indoor use.

Type 8 NEMA

Type 8 NEMA enclosures offer the same protection as a NEMA 7 enclosure but can be used both indoor and outdoor hazardous locations.

Type 9 NEMA

Type 9 NEMA enclosures are dust ignition proof and intended for indoor use in hazardous locations.

Type 10 NEMA

Type 10 NEMA enclosures meet MSHA, the Mine Safety, and Health administration standards.

Summary

So, what have we learned?

National Electrical Manufacturers Association, or NEMA, is an organization that deals with technical standards for the manufacturing of electrical equipment and medical imaging equipment.

Most commonly, they are known for their rating system, known as NEMA Rating which classifies the level of protection an enclosure has against environmental elements. They are closely related to IP Ratings, but they allow for additional environmental elements such as corrosion.

NEMA is an American standard whereas IP is a European standard. NEMA ratings are used exclusively for enclosures, but IP ratings can be used for all kind of devices.

We’ve learned about each type of NEMA rating, and what protection levels they offer. Unlike IP ratings, the higher the number does not necessarily mean greater protection, and it very much depends on what you’re protecting against.

There is no direct correlation between NEMA ratings and IP ratings!

There is no direct correlation between NEMA ratings and IP ratings, but a Type 1 NEMA enclosure is similar to IP10, with a Type 6 NEMA enclosure being similar to IP67.

That’s it for this article! I hope you enjoyed learning about NEMA ratings and how they are related to IP ratings. Now you should have a greater understanding of what the NEMA enclosure rating system is used for, and how we are able to select the right type of enclosure to give us the required protection level of our system.

Thank you so much for watching, sharing, and encouraging this community with your voice. 

Got a friend, client, or colleague who could use some of this information? Please share this article.

The RealPars Team

By James Jowett

By James Jowett

Automation Engineer

Posted on Oct 28, 2019

By James Jowett

Automation Engineer

Posted on Oct 28, 2019

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