Published On: December 18, 2019

The International Electrotechnical Commission (IEC) and the National Electrical Manufacturers Association (NEMA) are the international and American bodies, respectively, governing the standards for design, production, and distribution of electrical, electronic, and rated technologies collectively referred to as “electrotechnical” products. So, what is the difference between the two standards?

International Electrotechnical Commission (IEC)

IEC, founded in 1881 and based in Geneva, Switzerland, is responsible for determining units of measure like Gauss (magnetic flux density) and Hertz (frequency cycles per second).  IEC standards are measured to very exacting levels and generate multiple options for a specific current or power rating.

IEC Benefits

The benefits of IEC components

  • Finger-safe
  • Low profile
  • Generally cheaper

National Electrical Manufacturer’s Association (NEMA)

NEMA, founded in 1921 and based in Washington, DC, allows a 25% ‘service’ variance to enable multiple manufacturers to meet specific standards. These standards ecompass a broader range of service levels and specifications. Consequently, NEMA standards often result in larger and more expensive components, which are more versatile and more resistant to short circuits.

NEMA Benefits

  • Larger
  • More versatile
  • More resistant to short circuits
  • Require safety covers

What Are IP Ratings?

Electrical connections are often enclosed or encased in plastic to protect them from dust or water damage. The rating of this encasement is known as the Ingress Protection Marking (IP Marking) when set by the IEC, or the enclosure classifications set by NEMA.

Because NEMA standards exceed IEC standards, NEMA enclosure classifications can be converted to comparable IEC IP markings, but the conversions do not work in the other direction, from IEC to NEMA standards. NEMA provides a comparison of its NEMA 250 Enclosures for Electrical Equipment (1,000 V Maximum) and IEC 60529 Degrees of Protection Provided by Enclosures (IP Code) on its website.


JEM cable assemblies and wire harnesses are manufactured to adhere to NEMA standards. This benefits JEM customers by ensuring that our products are suitable for a broad range of applications and a wide range of capacity, and are less likely to short circuit than more compact products designed under more narrow IEC standards.

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