Don’t Get Left in the Dark: Updated NEC Definitions & Terms

Don’t Get Left in the Dark: Updated NEC Definitions & Terms

The industry is abuzz about the significant changes in the forthcoming 2023 Edition of the National Electrical Code® (NEC®), but as a field evaluations/codes and standards trainer, I think it’s important to understand our basic terms and how they are used. The NEC Style Manual helps to ensure our code is as clear and concise as possible to promote a uniform understanding of the requirements. The revisions to the 2020 NEC Style Manual continue to impact the 2023 edition of the NEC.

By Christine Porter, Field Evaluations/Codes and Standards Trainer, Intertek


The NEC® is used nationally and internationally as the basis for safeguarding persons, buildings, and their contents from hazards arising from the use of electricity. It is vitally important that the text be as explicit as possible and that maximum consistency is achieved in the language used in the text. The Code contains those provisions considered necessary for safety and thus is widely used as a basis for legal enforcement in the installation of electrical conductors and equipment in buildings and certain other premises (as detailed in the Code itself); this places a major responsibility on those involved in the preparation of document text to use forms of expression that promote uniform interpretation.”

This idea is further clarified in the stated purpose of the NEC Style Manual in section 1.1:

1.1 Purpose. The National Electrical Code (NEC) Style Manual is prepared under the guidance of the NEC Correlating Committee and is used to advise members of the National Electrical Code Committee and the Technical Committee on Electrical Safety in the Workplace on the required editorial style and arrangement of their respective documents. It is intended to be used as a practical working tool to assist in making the documents as clear, usable, and unambiguous as possible.”

Moving all the definitions to one article helps ensure that among the 18 code-making panels (CMPs), there is a common understanding of the terms defined and used in the NEC. This, in turn, makes it easier for the code user to understand the terms and how they are used. In instances where there were multiple definitions of the same term but each slightly different, they have been combined into one term or identified as being applicable for use in just one article.

The structure of the definitions was changed in order to organize the terms in alphabetical order by groups. For example, there are more than 30 defined types of cables in Article 100. To make it easier to find them all, the first word is “Cable” or “Cables,” the base term, followed by the modifier. The common name follows in parentheses as the words that will appear within code text. If acronyms are used, they follow the base term in parentheses. If a term is limited to just one article, that article number follows the searchable term. Users of the NEC can also see who controls the definition by the responsible CMP indicated at the end of the definition. Examples of the newly structured definitions are included below:

  • Cables, Abandoned. (Abandoned cables) (CMP-16)
  • Cable; Armored (Type AC). (Armored Cable)(CMP-6)
  • Cable, Circuit Integrity (CI). (Circuit Integrity Cable) (CMP-3)
  • Cable, Flat Conductor (Type FCC). (Flat Conductor Cable (324)(CMP-6)

This revision is important because it makes the terms searchable not only by alphabetical order but also includes an alternate term that is used for the cables to create clarity for the user. Acronyms are also indicated when used.

To ensure that we all understand the definition of the terms, it is important to review them so that we fully comprehend the meaning of the term and how it impacts our installations. One example of misusing a term occurs when discussing grounding and bonding issues. Many people will refer to a “grounding conductor.” The problem is that term is not a defined term, which in turn does not let the users and inspectors know how to size that conductor, what color it is permitted or required to be used, or how or where it is installed in an electrical installation. A vague term like this leads to a number of questions for interpretation. We all need to know if it’s an equipment grounding conductor? Is it a grounded conductor? Is it a grounding electrode conductor? Each has a different and important safety function.

As you can see, if the correct term is not used, it is possible to have an installation that is not safe and does not provide the needed safeguards from the hazards of using electricity. With the updates to the revised NEC Style Manual to make the definitions explicit and the language consistent, as well as relocating all definitions to a single article, there is less room for interpretation by the code user, leading to fewer errors during installation.

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