Article 90: Why It’s So Important for Electrical Inspectors
Some people may not consider Article 90 of NFPA 70®, National Electrical Code® (NEC®), to be a backbone of electrical inspector knowledge.
But a familiarity with Article 90 is crucial for electrical inspectors. The sections found within Article 90 provide a comprehensive overview of when the NEC applies and when it doesn’t, how the code is arranged, and how enforcement works—all information that is valuable to any electrical inspector.
In this blog, we’ll go over some of the information in Article 90 that is important for electrical inspectors to know.
What does the NEC cover?
Section 90.2(C) lists areas covered by the NEC, and they are:
1. Public and private premises, including buildings, structures, mobile homes, recreational vehicles, and floating buildings
2. Yards, lots, parking lots, carnivals, and industrial substations
3. Installation of conductors and equipment connecting to the supply of electricity
4. Installations used by electric utility, such as office buildings, warehouses, garages, machine shops, and recreational buildings, that are not an integral part of a generating plant, substation, or control center
5. Installations supplying shore power to ships and watercraft in marinas and boatyards, including monitoring of leakage current
6. Installations used to export power from vehicles to premises wiring or for bidirectional current flow
As you can see, the NEC addresses installations and methods of accomplishing those installations in its areas of coverage. The fifth item was added in the 2020 edition of the NEC to address installations of shore power and associated receptacles in marinas and boatyards, which may help lower the risk of exposure to electric shock drowning (ESD) through specific changes made in Article 555. The sixth item was also added in the 2020 NEC to deal with new technology around electric vehicles (EVs) and their ability to provide power to premises electrical systems through the EV charging equipment. The changes are reflected in Article 625.
What doesn’t the NEC cover?
Just as important as knowing what the NEC covers is knowing what it doesn’t. Section 90.2(D) lists the areas that are not under the purview of the NEC, which helps electrical inspectors navigate the out-of-bounds line. This is not to say there are no electrical inspections happening in those areas—just that if there are any, they are likely done using a code or standard other than the NEC for determining compliance. For example, utility-owned service or transmission line installations are covered by the National Electrical Safety Code (NESC) and not the NEC.
How is the NEC arranged?
The NEC arrangement is outlined in Section 90.3. The NEC is organized so that the requirements found in Chapters 1 through 4 apply generally to all electrical installations referenced in the code, except those referenced in Chapter 8, where the code language must have specific references to the first four chapters. This arrangement helps consolidate general requirements into a few chapters so that they’re not repeated elsewhere in the NEC, which makes it easier for electrical inspectors and installers to locate.
Information for electrical inspectors around enforcement, interpretations, specific requirements, and what to do with new products, constructions, or materials is found in Section 90.4. According to 90.4(A), the NEC is suitable for mandatory application by governmental bodies that have legal jurisdiction of electrical installations. These bodies are usually state, county, or city governments that incorporate the NEC by reference into their rules or laws.
In most instances, electrical inspectors must be working under the authority of an enforcing agency or for an authority having jurisdiction (AHJ) to have any enforcement powers over permitted electrical installations within those jurisdictional boundaries. AHJs have the responsibility for making interpretations of the rules and for deciding on the approval or rejection of equipment or materials used in electrical installations. They may also grant special permission in certain circumstances as they deem necessary.
There are two types of rules in the NEC: mandatory and permissive. They are expressed very differently. Mandatory rules are the shall or shall not rules. For example, a mandatory rule would be “the electrical connection of conductors to terminal parts shall ensure a mechanically secure connection without damaging the conductors,” whereas a permissive rule would be “reconditioned equipment shall be permitted except where prohibited elsewhere in the NEC.” As a former AHJ, I frequently would tell electrical inspectors that the code isn’t what you THINK it says; it is what it SAYS it is, so go read the code section before writing a violation or approving an installation. Understanding the difference between mandatory and permissive rules can help the enforcer-installer relationship by having a more accurate inspection.
Where to go for more information
Electrical inspectors, you are not alone in what you do. NFPA® has an Electrical Inspection Section membership just for you, where you can network with other electrical inspector members. Inspectors can share ideas, talk code, and collaborate on interpretations of the code through NFPA XchangeTM. Having these tools will help create a more consistent enforcement of the NEC.