If you’re referring to a particular requirement in the NEC, do you reference a subpart or a subsection? And since the NEC is organized into nine chapters, why don’t we refer to the next level of division down as subchapters instead of articles? And what if you are referring to an OSHA regulation? Or an industry standard published by ANSI or IEEE?
There’s not a universally correct way that applies to every standard, reference, and regulatory publication used in this industry. Of course, you don’t want to come across unknowledgeable when speaking to others or writing up a report so getting the terminology correct for a given document is important. Yet, we don’t find “subsection” defined in Art. 100 of the NEC.
The correct answer to the NEC question posed at the outset is this: Each of the nine chapters is divided into articles (see Figure 90.3). Each article is, in turn divided into sections. Each section further divides down into subsections. As these nest, each further division is a sub, as in sub-subsection. How these are enumerated in the NEC has changed over the years. Here is an example of the current enumeration, from Art. 210: 210.5(C)(2)(2). In some previous edition, that would have been rendered in alternating numbers and letters: 210.5(C)(2)(b). When you are trying to follow a deep nesting back to the Section, it can be challenging. Use the context to help guide you.
What about other standards?
Let’s look at OSHA. As you page through 29CFR1926 (OSHA Construction Industry Regulations & Standards), at first glance it seems some of the OSHA regulations are arranged into Sections and some into Subparts. But the proper way to use a standard you aren’t familiar with is not to page through it but to turn to the Table of Contents (TOC) to get a feel for what’s in there and how it’s arranged. This will apply to any standard. In the case of 29CFR1926, we can readily see there are several main divisions:
- Part 1903, which is divided into Sections 1 through 22. Though these aren’t called “Sections” in the TOC, they are sections and we’ll see why in a moment.
- Part 1904, which is divided into Subparts A through G.
- Selected 1910 General Industry Standards.
- Appendix A.
- Addendum.
So how do we know 1903 and 1904 are Parts? If you turn to 1903 or 1904 in the body of the book, you will see the number preceded by the word “Part”. Each of the Subparts in 1904 is similarly preceded by the word “Subpart.” And if we look at something like 1910.1200 (Hazard Communications) and read the purpose [1910.1200(a), the first few words are “The purpose of this section….” So now we know that each division of 1910 is a Section. Which would then have subsections.
The need to get the nomenclature right is one reason not to just flip open a standard and hope you find the relevant regulation or requirement. You need to take the time to become familiar with the standard, so you understand the context of what you are reading. Sometimes, this is forced on the reader. For example, to be able to understand and correctly apply Arts. 501, 502, or 503 of the NEC you must first have a working knowledge of what’s contained in Art. 500.
And it’s not just the context you need to understand. If the standard uses words a particular way to mean particular things and you read those words some other way, you will fail to correctly apply the regulations or requirements therein. Look for an equivalent of the NEC’s Art. 100 and make a few passes through it so you get the intended meaning of what you are reading in the standard or regulatory document.
