Nema vs IEC Cords: Did you know this?

Two different standards. Used for different purposes. So similar yet so different!

NEMA and IEC are two known names when it comes to power cords and related stuff. But from an end user’s point of view, it is important to know the actual difference between these two.

Read along to understand their major differences and find out which one is the best fit for your application.

IEC Standard Power Cord

International Electrotechnical Commission (IEC) is a non-profit, non-governmental international organization. It develops and publishes international standards for all electrical, electronic and other related technology. It started in 1906 and has developed some well-known units of measure like Hertz and Gauss.


Today it works with the International Organization for Standardization (ISO) and the International Telecommunication Union (ITU) to define global standards for over 40 sub-categories of electrical components.

Some Highlights of IEC Power Cord:

  • Cost-effective
  • Compact
  • Reacts quickly to overloads
  • Inherently finger-safe

NEMA Power Cord

The National Electrical Manufacturers Association (NEMA) is the largest trade association of electrical equipment manufacturers in the United States. Founded in 1926, NEMA asked all the manufacturers to utilizes a standard frame size for their electrical components. This standardizes the components from different manufacturers and also gives them guidelines to develop the components with safety factors over and above their design ratings.

nema power cords

Some Highlights of NEMA Power Cord:

  • Good for enduring short circuits
  • Suitable for a broad range of applications

The Difference


  • NEMA: North Americans primarily use this standard and the people doing businesses hugely with North America. These are the general benchmark for technical requirements.
  • IEC: This standard applies to multiple countries. They are the general benchmark for technical requirements globally.

The Selection:

  • NEMA: It is easy to select. Know your horsepower and voltage and you will find your cord.
  • IEC: You will need more details for the selection process. Like Motor load, duty cycle, and full load current.

The Production:

  • NEMA: Its product design focuses mainly on the ability to use the products in a wide range of applications. Most people who use this standard have general requirements.
  • IEC: These products are generally smaller and less expensive. They require more details and well-defined operating conditions.
  • NEMA: Most of the NEMA products come fully assembled. But you can customize some of the products like interchangeable thermal units.
  • IEC: With IEC products, these starters come as separate components. It comes with a contractor, an auxiliary block, and an overload relay block.

The Security:

  • NEMA: These devices can withstand short circuits with built-in reserve capacity.
  • IEC: IEC starters include single-phase detection with faster reaction to overload conditions.
  • NEMA: As NEMA starters have an open design, they require safety covers.
  • IEC: IEC contactors and starters are finger-safe.

The Takeaway:

The main difference between IEC and NEMA is that NEMA by design may save up to 25% service while IEC is more about space and cost savings. For example, AC-1 handles purely resistive loads or slightly inductive loads like a heater. Another utilization category AC-3 is for regular starting and stopping of squirrel cage size motor. AC-4 is similar to AC-3. But it includes inching and plugging.

Common Misunderstandings

Considering both the siders, NEMA looks larger than the IEC starter. But in reality, it is slightly oversized in design. Often the wrong IEC classification for any application can be utilized. Overall when you decide between IEC or NEMA, make sure you keep in mind your requirements, the specialization, and your budget. If you are looking for easy-to-select, long-lasting products then NEMA can be a perfect choice. On the other side, if you have specialized needs, you can go with IEC products. But most importantly, if you are in North America, you’ll likely be able to source NEMA products with more ease. And IEC in European parts.

There are instances when each classification has its own merits. IEC is less expensive and smaller but it has well defined operating conditions. When it comes to devices whose load is not well defined, NEMA devices would be the best choice. Overall it is not as simple as we often make them. It is also not about which one is more robust and effective. But it is all about understanding your requirements and differences between the two systems and selecting the one which is proper for the job.