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NEC Development and Adoption

“Doesn’t the new edition apply everywhere?”

The National Electrical Code® (NEC®) is an essential document for anyone who specifies, installs, or inspects electrical equipment, but the adoption of its new editions can be uneven from region to region. This article summarizes how the NEC is developed and then adopted across the USA and in other countries.

NEC Development and Publication

The National Fire Protection Association (NFPA®) issued the 2020 Edition of the NEC late in 2019. A document with a long history, the newest version supersedes the 54 prior versions that have been issued since 1897. The document provides effective guidance for reducing risks of electrical hazards to people and property from electrical equipment and systems. Nonetheless, it is revised every three years to address emerging technologies and issues. To better understand why, consider the 2003-2018 electrical safety statistics for US workplaces, as summarized by Electrical Safety Foundation International.

There are many stakeholders to this document. Engineers, electricians, equipment manufacturers, code officials, policymakers, and end-users each have important interests. To ensure each is fairly represented, the NFPA follows an open process developed by the American National Standards Institute (ANSI) to bring forth new editions. Key elements of the process include (1) participation by experts that represent the range of stakeholder interests, (2) public participation and comment, and (3) subsequent revision and publication. In practice, this is a large effort … the 2020 NEC resulted from 18 separate code-making panels, 3,730 public inputs, and 1,930 comments on the initial draft. Available by subscription and other means, free access to several editions of the document can be found on the NEC website.
More information at https://www.ansi.org/about/roles, accessed December 2, 2020

NEC Adoption Processes

The revision of the NEC is a necessarily large but organized effort. The process for adopting the code can be a little less so.

Adoption proceeds on a state-by-state basis, and the length of time that elapses before adoption varies widely by state. For example, since 2008, The Commonwealth of Massachusetts has approved each new NEC edition within six months of issuance, while the State of Florida has taken 38 to 53 months to do the same. Furthermore, some states such as Tennessee have skipped entire editions, and some like the State of Pennsylvania continue to use the 2008 Code. In general, adoption proceeds more quickly in states that require electricians to be licensed and states that have a dedicated board of electrical experts. To see these and other interesting comparisons, review this NFPA report.

Status of Adoption by US States

Most states apply the NEC statewide. The states that have adopted the NEC are shown in the figure below, which is color-coded to indicate the NEC Edition in effect. A few states leave adoption to county or municipal agencies.
The International Association of Electrical Inspectors (IAEI) provides a handy tool for identifying the adoption scheme for each state. Links on their webpage Browse NEC Adoptions and Electrician Continuing Education Requirements by State show that The State of Kansas applies the 2008 NEC to state-owned buildings, and relegates code adoption for other applications to local authorities, for which the page supplies notable examples. Elsewhere, the State of California link shows that California has adopted the 2017 NEC. More specifically, the subsequent link to the California Building Standards Commission shows that the NEC has been incorporated into California’s 2019 Triennial Edition of Title 24, where Part 3 is identified as the California Electrical Code.

NEC Adoption Outside of the USA

The NEC is referenced or used in regions outside of the USA. Canada and Mexico use codes that parallel the NEC but are adjusted for conditions and historic practices in those countries. The Canadian Electrical Code was last released in 2018, and Mexico’s Standard for Electrical Installations (Utility), NOM-001-SEDE was promulgated in 2019.

Some countries in Central America also base their regulation of electrical safety on the NEC. The NFPA site indicates that Mexico, Guatemala, Nicaragua, El Salvador, Honduras, Costa Rica, Panama, the Dominican Republic, Colombia, Ecuador, Peru, and Venezuela rely in some way on the NEC. For these countries, The NFPA Journal is available in Spanish language at https://www.nfpajla.org/, and NFPA training is likewise available at https://www.estudionfpa.org/.


The National Fire Protection Association develops new editions of the NEC using an open American National Standards Institute accredited process. This seeks input from a broad range of experts as well as public participation and comment. The NEC was most recently published as the 2020 Edition. Adoption has proceeded on a State-by-State basis, as described herein and shown in the Figure above. In addition, the NEC is used as a basis for regulation of electrical safety in Canada, Mexico, and several countries in Central America.

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