There is some confusion in the electrical industry with respect to the application of arc flash equipment labeling as seen in NFPA 70E Section 130.5(H). The question is this: when is arc flash equipment labeling an installation requirement in new construction and renovation?

NFPA 70E does not contain any installation requirements. The standard addresses electrical safety-related work practices, safety-related maintenance requirements and other administrative controls for workplaces that are necessary to provide a practical, safe working area for employees relative to the hazards arising from the use of electricity. The National Electrical Code contains the minimum installation requirements and does address requirements for arc flash equipment labeling on a very limited basis.

The scopes of the NEC and NFPA 70E very clearly exclude installations under the exclusive control of an electric utility. This means OSHA requirements for transmission and distribution apply only on the line side of the service point as defined in the NEC. Applicable OSHA requirements on the load side of the service point do not mandate arc flash equipment labeling.

Equipment labeling in NFPA 70E Section 130.5(H) includes labeling of the nominal system voltage, the arc flash boundary and at least one of the following three list items: (1) the available incident energy and the corresponding working distance or the arc flash PPE category for the equipment, but not both; (2) the minimum arc rating of clothing; or (3) a site-­specific level of PPE.

It is extremely important for the NFPA 70E user to read and understand the last sentence in Section 130.5(H). This sentence clarifies that the electrical equipment’s owner is responsible for the documentation, installation and maintenance of the marked label. If the owner chooses not to label the equipment and there is not an installation requirement in the NEC mandating labeling, the discussion ends because NFPA 70E does not contain installation requirements.

NEC Section 110.16, Arc Flash Hazard Warning, first existed in the 2002 edition. It requires a generic marking that can be field- or factory-installed to warn qualified people of potential arc flash hazards. This is not an equivalent to the equipment labeling requirements in Section 130.5(H) of NFPA 70E. This label is required on equipment, such as switchboards, switchgear, panelboards, industrial control panels, meter socket enclosures and motor control centers, that are in buildings other than dwelling units and are likely to require examination, adjustment, servicing or maintenance while energized. The warning label must be located so as to be clearly visible to qualified people before equipment examination, adjustment, service or maintenance.

In 2017, Section 110.16(B), Service Equipment, was added to require a more prescriptive labeling requirement. This section applies only to service equipment in sites other than dwelling units where the equipment is rated 1,200A or more. These labeling requirements are very carefully crafted to prevent scope creep between the NEC and NFPA 70E. The required labeling includes the nominal system voltage, the available fault current at the service overcurrent protective devices, the clearing time of service overcurrent protective devices based on the available fault current at the service equipment and the label’s date of application.

Not many installations were labeled in this manner because an exception permits an arc flash label to be applied in accordance with acceptable industry practice, which is NFPA 70E Section 130.5(H). The NEC technical committee responsible for crafting the text in this requirement had to be careful not to use terms such as incident energy or arc flash PPE tables, as those terms are not within the NEC’s scope.

During the first draft meetings for the 2023 NEC, the requirements for arc flash equipment labeling were changed significantly. The title of Section 110.16(B) is modified to include “Service Equipment and Feeder Supplied Equipment.” The ampere threshold for the required labeling is reduced from 1,200A to 1,000A, and this new marking is specifically referred to as an arc flash label. The previous list of prescriptive information on the label was deleted, and the requirement now mandates an arc flash label be installed in accordance with acceptable industry practice (NFPA 70E) and must include the date the label was applied.

This revision very clearly mandates arc flash equipment labeling in accordance with 130.5(H) in NFPA 70E for all service and feeder supplied equipment rated at 1,000A or more. There is one significant difference in this labeling—the NEC mandates marking the date the label was applied.

The evolution of safety-driven requirements in the NEC and NFPA 70E shows how the documents work in harmony to provide electrical workers with a practical safe working area relative to electrical hazards.