NEMA VS IEC: Know All About These Electric Motor Standards


For electric motors and their controls, industries use different standards. These are NEMA vs IEC, and they help the control panel builders to pick suitable products. In North America, mostly NEMA standards are in use, while IEC is in use in most parts of the world. The two standards do not mean that the motors are different. The output power, size, and efficiency of the NEMA and IEC motors are the same. So, what’s the difference between these two? In this article, we will go through the features of NEMA VS IEC.

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Electric motor

Image: Electric motor


IEC is a non-governmental and non-profit organization founded in 1881 with its head office in Geneva, Switzerland. The association prepares global standards for electronic, electrical, and rated technologies. 

The IEC has developed several units of measure such as Hertz and Gauss. Earlier the IEC standards were in use mainly in the European market. However, now numerous companies in the US and North America also use IEC-certified components. IEC-rated parts are cheap, safe, and compact to use.


Founded in 1926, NEMA is the largest trade association in the US for electrical equipment manufacturers. The association gives the standards for the different components for motor control and lighting applications. It also sees if industries design components to meet safety standards over their design ratings. The set-up and performance parameters of different electrical components also come under its criteria.

NEMA VS IEC--Extension cable and plug NEMA connector

Image: Extension cable and plug NEMA connector

Industries that manufacture components related to power generation, control, distribution, the transmission must follow NEMA standards. NEMA gives standard frame sizes for electrical components.

NEMA VS IEC– Fundamental differences between NEMA and IEC

The NEMA and IEC products differ. However, applying both styles gives flexibility, and you can quickly adapt to local needs and product supply. However, to get this flexibility, let’s understand some critical differences between NEMA and IEC.

Different philosophy:

NEMA focuses more on the product’s robustness, and their robust nature makes them suitable for a broad range of applications, and NEMA components are more for general purposes. NEMA Industrial Control Standard (ICS-2) controls the design of NEMA motor control devices. 

However, IEC products need specific and well-defined working conditions. They are small and less expensive than NEMA products, and you can quickly service a NEMA product as you can access internal parts. 

Knowledge and training:

NEMA products offer you the ease of selection, and you only need to know horsepower and voltage for the application. On the contrary, you must know motor load, total load current, and duty cycle to select an IEC contactor.

The state of the market:

Firstly, industries use NEMA mainly in North America or areas that work on North American business and technology. On the other hand, multiple countries combinedly developed IEC. For technical requirements, IEC standards are in use on a global level.

NEMA VS IEC– Safety:

One of the primary differences is that there is an open design in NEMA starters. As a result, you need safety covers. On the other hand, IEC motor starters and contactors are finger-safe.

Device size:

NEMA mainly focuses on target devices, while IEC ratings are more suitable for compact devices globally.

NEMA VS IEC–Some other differences:

  • Due to a built-in reserve capacity, NEMA devices can easily bear short circuits. On the other hand, IEC motor starters have single-phase detection and faster reaction to overload conditions. 
  • You can change the heater elements of the NEMA devices. Also, you can find a range of units for overload. Thus, NEMA products are more favorable for construction jobs. At the same time, IEC focuses more on IP ratings.
  • The given current ratings of the IEC contactor are smaller than the NEMA contactor.


Then, IEC vs NEMA: which is the best? First, you have to choose how specific a product you want. Also, how much can you invest? NEMA is a good choice if you want an easy pick that can last for a more extended period. However, if you want something particular to your needs, better to go for IEC. Another factor to consider is the region. If you are near or in North America, NEMA is undoubtedly the better option for you. For other areas, go for IEC. Industries have tried to standardize the ratings, so you may not see any significant difference in them. However, before picking either of the two products, you must see what the rating says.

At Cloom, we offer a wide range of cable assemblies to support the NEMA and IEC standard devices. Contact us.