Arc flash labels are placed on electrical equipment to provide warning of the potential arc flash hazards present during energized or potentially energized work and to document the required PPE. Arc flash labels should be located in a place that is easily visible and readable from some distance.
Consistency in the format of the label and its location on the equipment helps in compliance with arc-flash PPE requirements. An example arc flash label is shown below. NFPA 70E-20213 Article 130.5 (H) covers the minimum requirements for arc-flash labeling. The following information is required on the label:
Site-specific level of PPE
NFPA 70E is not specific about details such as the size of the label, location and quantity of arc flash labels, or the use of “Warning” versus “Danger.” Also, although it is common to include the shock risk assessment information on the label, 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 equipment where a maintenance mode setting is being employed to reduce the incident energy and resulting PPE requirements, the labeling 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 key final step in the arc flash study is to ensure that the correct arc flash label is applied to each piece of equipment. To minimize errors, the naming of equipment on the one-line diagram should match the actual names shown on the equipment.
Updating the Arc-Flash Study
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 but also states that arc flash labels do not have to be updated just because the label requirements in the standard change unless the actual system has changed. The single-line diagram should be kept up to date as changes are made and arc flash results recalculated whenever equipment is changed out or upgraded.