IEC vs. NEC: Similarities and Differences

IEC and NEC logos

While it may seem fairly common and a foundational building block of the industrial electrical industry, you’d be surprised how few people can accurately describe the differences between IEC and NEC. Some of the differences are glaringly obvious while others are more nuanced. In this post, we will break it down into simple and understandable terms.


The IEC, which stands for the International Electrotechnical Commission, is the European framework for “electrotechnology”. The Commission itself is a non-profit, non-governmental agency that formed at the turn of the 20th century as the proliferation of electrical energy started to occur. Smartly, leaders in Europe realized that there should be a common set of rules for managing this and thus the IEC was born. In one sentence, the IEC sets standards for the installation and management of electrical systems in Europe and beyond.

The IEC brings together 170 countries, 83 members and 87 affiliates. They cover the world, not just Europe. The United States is a full member of the IEC. The IEC standards published by the Commission have numbers ranging from 60000–79999 (don’t ask us why it starts with 6000). We were fortunate enough to get feedback from Gabriela Ehrlich, IEC Global Head Public Affairs & Advocacy. She offered us the following additional insight on the IEC:

We develop approx. 10 000 International Standards and we administer also 4 Conformity Assessment Systems, whose members test and verify that products deliver what they promise. 80% of European electric and electronic Standards are IEC Standards. Likewise many US companies who want to export build their products to IEC Standards.


What’s important to note is that the IEC publishes standards, not mandates. We will explain why this matters later on. Again, here’s Gabriela’s official take on this:

IEC International Standards are voluntary, consensus based. Only when regulators adopt them into their laws will they be enforced



The NEC stands for the National Electric Code. The code itself is written and published as part of the National Fire Codes by the National Fire Protection Association (NFPA), a private, non-governmental organization. The code is updated and republished every three years by a group of panels. The original intention of the NEC mirrors the IEC with the exception being that the scope was more narrow and focused only on North America. In one sentence, the NEC writes code for the standard installation of the electrical system in the United States.

While all 50 states have adopted the NEC, there are also some Central and South American countries such as Costa Rica, Venezuela, Columbia, and Mexico. It’s also important to note that the NEC is not followed in Canada. As mentioned, the output of the code itself is a piece of literature which is updated to ensure that the code is up to date. Lastly, while the NEC is not a governmental regulation or a government entity, those who violate the code (whether knowingly or unknowingly) can be prosecuted for negligence.

IEC & NEC Similarities

While not exactly the same, there are certainly correlations between the IEC and the NEC.

  1. They both set frameworks and provide a common set of standards to follow for electricity
  2. They both act as non-governmental authorities
  3. They both serve multinational entities (with the IEC being more all-encompassing)
  4. They are regularly updated and have governing bodies

IEC & NEC Differences

In reality, the IEC and NEC have quite a few important differences.

  1. While both the IEC & NEC set a framework and provide standards, the IEC does not write enforceable electrical code. The NEC should be thought of as a set of specific guides and directions that should be precisely followed. The IEC does not go this far and thus is more generic than the NEC. Summarized, the IEC is meant to be consulted and considered; the NEC is meant to be meticulously followed.
  2. The primary concern of the NEC is safety whereas the primary concern of the IEC is harmonization. This makes sense when you consider their original charters. The IEC was meant to create harmony amongst the major European countries (just like a common currency) and promote trade. The NEC was meant to give electrical installers, designers, and inspectors in the United States with the means to wire electrical devices.
  3. Interestingly, the IEC is not comprehensive and completely uniform. Supporting documents must be consulted and there are some gaps. The NEC, however, is intended to be an all encompassing document.

Wait, What If They Conflict?

We get this question a lot. Simply put, it depends on where you reside. If you are in the United States, NEC always wins. if you are in the UK, it would be reasonable to assume that you follow IEC, right? Not so fast! As we mentioned, the IEC is not all-encompassing so you would need to consult the local regulations and variances from the IEC framework. It can be further understood for the UK specifically here.

Summing it Up

We believe that the best way to explain the IEC and the NEC is to use an analogy. We consider the IEC to be the European “Constitution” of Electricity. It is meant to be interpreted and leaves room for debate and nuance. It also is not all encompassing and must be supplemented with various “Bill of Rights” from member nations. It is meant to be a guiding light for electricians.

We consider the NEC to be similar to the US Tax Code of Electricity. It is largely fixed, must be rigidly followed, and contains consequences for those who choose to evade it.

What did we miss? Share your thoughts below!