Arc flash labels are essential to electrical safety in workplaces with energized electrical equipment. They provide critical information about the potential hazards and the required PPE for workers. By following the labelling requirements set forth by NFPA 70E and keeping the arc-flash study up to date, employers can help ensure that workers are protected from the risks of arc flash and other electrical hazards.
Arc flash and shock hazard is a severe electrical safety concern that poses a risk to workers who work on or near energized electrical equipment. To help prevent injury or death, arc flash labels identify potential hazards and document the required personal protective equipment (PPE).
Electrical equipment is often labelled with arc flash labels to alert about potential hazards and shows that ppe and tools are required. The labels should be placed in a location that is easily visible and readable from some distance. Consistency in the labels' format and location helps comply with arc-flash PPE requirements. NFPA 70E-2021 Article 130.5 (H) covers the minimum requirements for arc-flash labelling and specifies the information that must be included on the label.
The label must include the nominal system voltage, the arc-flash restricted approach boundary, and the arc-flash hazard-appropriate PPE required. In addition, at least one of the following must be included: available incident energy and the corresponding working distance or arc-flash PPE category in NFPA 70E Table 130.7(C)(15)(a) or Table 130.7(C)(15)(b) for the equipment, but not both. The minimum arc rating of clothing and the site-specific level of PPE must also be included.
Although NFPA 70E is not specific about details such as the label size, location and quantity of arc flash labels, or the use of it is important to ensure that the labels are clearly visible and easily readable. Additionally, while including the shock risk assessment information on the label is expected, as in Figure 4.5, this is not required on the label per NFPA 70E-2021. There are many label templates to choose from that allow full customization of the label information.
An exception in 130.5(H) also allows other forms of documentation to be used in lieu of labels in supervised industrial installations. For example, in cases where a maintenance mode setting is employed to reduce the incident energy and resulting PPE requirements, the labelling must clearly indicate this, or the label should give the worst-case arc-flash energy with the maintenance mode reduction covered in the Energized Work Permit.
One of the key steps in an arc flash study is to ensure that the correct arc flash label is applied to each piece of electrical equipment. To minimize errors, the naming of equipment on the one-line diagram should match the actual names shown on the equipment.
It is also essential to keep the arc-flash study up to date. NFPA 70E recognizes the need to periodically review the results of the arc flash study for accuracy whenever power system changes are made and at least once every five years. However, it is unnecessary to update arc flash labels just because the labelling requirements in the standard change unless the actual system has changed. Instead, the single-line diagram should be kept up to date as changes are made, and arc flash results should be recalculated whenever equipment is changed out or upgraded.