The relationship between NEC, UL, NRTL, NFPA 79, “Listed” and AHJ in industrial electrical installations

by | Oct 24, 2019 | Wire & Cable

Adopted in all 50 states, the National Electric Code (NEC) or NFPA 70 is the set of rules and regulations for safe electrical design, installation and inspection of electrical wiring and equipment in residential, commercial and industrial occupancies alike. Whether you’re wiring a house or an automotive plant in the US, you’re doing so by the NEC. It is part of the National Fire Code series published by the National Fire Protection Association (NFPA) but the NEC is not a federal law. While it’s adopted as a standard in the US, there are other factors, organizations and certifications that play a role in promoting the safe use and installation of electrical equipment.

“Listed” is a term found in some but not all codes and standards in the NEC. Keep in mind that “listed” does not mean “UL Listed” nor does it mean the product has been “approved”, both common misconceptions. The term “Listed”, according to the NEC means that the equipment, materials or services are included in a list published by a Nationally Recognized Testing Laboratory (NRTL), a private-sector organization appointed by the Occupational Safety and Health Administration (OHSA) to perform evaluation, safety testing and certification of products, using consensus based test standards, for safe use in the workspace.

Manufacturers submit products to a NRTL for testing and safety certification on a voluntary basis to get their product “listed”. There are no laws specifying that listed products must be used however, in the United States many municipalities have laws, codes and regulations which require a product be certified by a nationally recognized testing laboratory before it can be used. Products which carry listings and are labeled as such are quickly identified by the authority having jurisdiction, or inspector to satisfy strict safety requirements.

There are several of these laboratories listed by OSHA however, with over 125 years of testing and certifying, UL or Underwriters Laboratory is the largest, oldest and most recognized of the group. There are a few types of UL certifications, including “UL Listed”, different from the NEC’s use of the term “listed”, explained in our article “Understanding UL Listed vs. UL Recognized for Wire and Cable”

While the NEC covers electrical products and installations in the field, NFPA 79 is the section that covers the products and installation on the machine, or the electrical and electronic equipment, apparatus, or systems of industrial machines supplied from a nominal voltage of 1000 volts or less. NFPA 79 is also voluntary and more of a best practice outline of standards for machine building across North America, however most states, local authorities and end customers in North America will demand compliance with NFPA 79.

At the end of the day, “approved” is defined in the National Electric Code (NEC ®) under Article 100 as “acceptable to the authority having jurisdiction”. The AHJ, or inspector, is responsible for interpreting and enforcing the requirements of a code (NEC) or standard (NFPA 79), or for approving equipment, materials, installation or a procedure as the final authority. They will often require products be listed with a NRTL and labeled as such as a basis for approval, so here again listings are important from an inspection standpoint, even if the NEC does not require it.

Right Hand Industrial offers a wide range of UL listed, Recognized, NFPA 79 compliant and multi-approval wire and cable for various industrial applications in a lean distribution model. This means we synergize the product portfolios, inventory and services of multiple manufacturers and master distributors across North America and we eliminate any non-value-added activity in the supply chain. This allows us to deliver in the most efficient and cost effective way possible. Contact us today to learn more about how Right Hand Industrial can be an effective extension to your purchasing and engineering groups or browse our online catalog

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