Arc Flash is the Target of NYC Electrical Code Update

Legislation upgrading the New York City electrical code was enacted in late December, the first upgrade since 2011. Local Law 128 of 2024 has significant implications for the safety of workers addressing the electrical infrastructure of buildings in New York City—and offers a model for buildings in other cities as well.

A major change is that now each piece of electrical service equipment located in a building’s electrical room—that is rated at 1200A or more, regardless of the voltage—is required to have an Arc Flash label, in accordance with NFPA 70E, the standard for electrical safety in the workplace. The label specifies the safety precautions, including protective clothing, that workers must use in servicing the designated equipment. 

An Arc Flash label is generated at the conclusion of an electrical study of the equipment and is then placed on that equipment. Per NEC 2020, section 110.16(B), the label must contain such information as the following: nominal voltage; available fault current at the service overcurrent protection devices; the clearing time of service overcurrent protection devices based on available fault current at the service equipment, and the date the label was applied.

The Arc Flash label makes the safety precautions highly visible and clear. It removes any doubt about what is needed and is, therefore, crucial to the safety of the workers. It needs to be updated every five years. 

While the primary objective of the label is worker safety, it also demonstrates to insurance companies that these safety measures were taken and are readily apparent. In the event of a worker injury, the property owner would have evidence that the required safety precautions were in place.

An Arc Flash electrical study provides a diagram of the electrical system being addressed. It also identifies potential mitigation measures that could be taken to reduce the energy in a particular piece of equipment to a lower safety threshold. Such mitigation measures would only be in areas where the levels of energy exceed personal protection equipment.

The New York City legislation addresses equipment in a building’s service room, typically a basement electrical room, but a property owner may wish to expand the electrical study to cover relevant equipment throughout the building. That equipment, specifically panel boards, is typically in a landlord’s closets, often one closet per floor. Building tenants would be responsible for their own panels in their spaces.

Here, too, the benefits from an insurance perspective are overwhelming. The cost of an electrical study, and the generation of Arc Flash labels, is a small fraction of the costs that might be sought in the case of an injured worker in the absence of Arc Flash labels. 

What the new legislation requires is limited to the service equipment, because that’s where the electrical fault current is highest and where the greatest safety risk exists. The risk decreases, as one goes higher in a building, because the electrical energy is then reduced due to the distance from the source. Still, the benefits of studying and addressing the entire building remain.

The legislation provides one year to do the work. It’s right to be emphasizing the importance of Arc Flash labels.

This Viewpoint is written by Vinod Palal, a principal and the director of electrical engineering at New York City-based consulting engineering firm Goldman Copeland.