The Elegant Interaction of Codes and Standards

By Michael Shulman, principal engineer, lighting

In the previous edition of Lumen Insights (Q2 2020), we covered some of the recently published revisions of UL 924, the Standard for Emergency Lighting Equipment. Product standard revisions are often in response to new product designs, and these product-level revisions usually lead to a National Electrical Code® (NEC) revision proposal, known as Public Input or PI, to clarify how these products must be installed. For example, the recently expanded UL 924 content related to emergency lighting control devices allows a PI for the 2023 NEC to require such devices to be listed in accordance with UL 924.

The product standard sets requirements for a product, while the code sets parameters around the installation of that product. But it also works in the other direction: if the code has an expectation for a product, the standard can be revised to ensure that certified products meet those expectations. The timing is interesting because there is no direct connection between the revision cycles or process of the standards and the NEC. The NEC has a fixed revision cycle, with a new edition published every three years. Product standards typically do not have a fixed revision cycle and can thus be revised more rapidly than the code (although that is not always the case for standards that are governed by international harmonization processes). The situation is further complicated because jurisdictions responsible for code enforcement (cities, counties and states) adopt newer editions of the NEC on their own schedule. UL’s policy is always to seek alignment with the most recently published NEC. At present, that’s the 2020 edition (published September 2019), and many standards are now being reviewed to determine if revisions are needed. These standard revisions and their potential impact on product certifications can create some confusion for jurisdictions that are still using earlier NEC editions (2017 or 2014) because the alignment between product requirements and code expectations might be less than optimal.

This is nicely demonstrated by Power over Ethernet (PoE) lighting, which was added to UL 924 with the May 2020 revisions, permitting such equipment to use its proprietary connection means (communication cables with a snap-in connector). But the 2020 NEC doesn’t accommodate this type of wiring for emergency luminaires. So PIs are being submitted for the 2023 NEC to identify and justify adjustments that allow this wiring method while retaining the reliability and level of protection expected for emergency systems.

The NEC alignment associated with the most common lighting standards is:

The 2023 NEC public input process is open until Sept. 10, 2020. The first draft report, which identifies the revisions approved by the various code making panels, will be published July 2021. Comments on the first draft are then accepted, with a second draft to be published March 2022. At that point, while there are still processes that can lead to further revision prior to final adoption, UL principal engineers will typically start their part of the process, considering what adjustments, if any, are needed to keep the Standard in good alignment with the next code edition.

This process isn’t always pretty; it can sometimes be clumsy, and awkward moments do happen. But it has successfully retained alignment between UL Standards and the NEC for many decades. There is an our safety infrastructure keep pace with ever-changing parameters.