Art. 90 serves as the prelude to the National Electrical Code (NEC), explaining how its requirements are enforced and who is impacted by the scope of its enforcement. For electrical apprentices and those new to the electrical industry, it helps you understand the sometimes fragile relationship between building inspectors and contractors. It also helps solidify your understanding of how consistent enforcement of the NEC creates installations that are essentially free from hazards and necessary for safety.
After reading this Article, you will understand:
- How and why the NEC is enforced.
- The responsibility of NEC adopters and limitations of the NEC.
- The range and scope of authority granted to inspectors [i.e., authorities having jurisdiction (AHJs)]
- The scope of the NEC — what it covers and what it does not.
The Code’s purpose
Art. 90 explains that the purpose of the NEC is to protect:
- Consumers of electricity
- Buildings and structures
- Electrical equipment and devices
Enforcers of the Code (i.e., AHJs), contractors, journeyman electricians, and apprentices need a universal and consistent set of installation guidelines to follow when providing electrical repairs and installation. Art. 90 [Figure 90.1] provides an illustrated directory to navigate thousands of guidelines organized in the NEC. This handy guide also explains how chapters overlap and affect one another. The NEC, its language, and enforceable guidelines are not suited for novices; it exists for electrical professionals.
Adequacy
The NEC is not designed to make electricians' lives easy or convenient; it provides a minimum level of safety guidelines to be followed. Electricians/installers are responsible for:
- Making provisions for future system changes.
- Making allowances for proper future maintenance.
- Designing electrical systems and services that are adequate for good service.
As electricians and technicians, one of our primary goals is to avoid overloading wiring systems. The onus is on you as a contractor, electrician, or apprentice to allow for future increases in electricity use as you design and install branch circuits and electrical systems.
Enforcement
The NEC gives governmental bodies (e.g., cities, townships, states) and insurance organizations a uniform set of requirements or practices to enforce. Enforcing the Code can also give a person responsible for implementing code requirements direction in approving electrical equipment, materials, and procedures. Because construction materials and methods vary from person to person, adoption of the NEC gives us a standard set of guidelines to follow no matter where (e.g., city, state) we work or what part of the industry we're in (e.g., residential, commercial, or industrial).
Mandatory application and enforcement of the NEC can reduce or remove ambiguity in electrical drawing(s). For example, the NEC helps contractors and inspectors identify omitted items on projects that may be in progress. The NEC also gives electricians and tradesmen/women a consistent set of rules to follow, which are imperative for safety. As electricians, our wiring techniques and procedures should drive our design and installation practices around a firm understanding of the NEC and its enforcement.
Informative Annex H
For an in-depth review of how the NEC is enforced and adopted within municipal departments, check out "Informative Annex H Administration and Enforcement" at the back of your Code book. It will give you more insight into how and why things are done from an inspector's standpoint.
Follow my column for more practical how-to articles and tips on electric basics and applying those concepts in the field, such as The Apprentice’s Guide to NEC Chapter 4, Everyday Instructions for Electricians, Introduction to Commercial Service Calculations, Introduction to Residential Service Calculations, and The Apprentice’s Guide to Non-Metallic Sheathed Cable. For more in-depth information on why a structured approach is so important to navigating the NEC and how to put its requirements into practice in real-world settings, read “The NEC for Newbies.”
Harold De Loach, a master electrician and electrical trainer/instructor, is the founder of The Academy of Industrial Arts (www.taia-school.com) in Philadelphia. With more than 30 years of experience in the field, he writes regular exclusive content for the E-Train and can be reached at [email protected].
