What Needs to Appear on the Label?

The current NFPA 70E edition requires these three elements to be included on Arc Flash labels:

1. At least One of the following:

• Available incident energy and the corresponding working distance. Incident energy is the amount of energy impressed on a surface, a certain distance away from the source that is generated during an electrical arc event. Incident energy is expressed in cal/cm2.
• Minimum arc rating of clothing. Arc rated clothing indicates it has been tested for exposure to an electrical arc. This was formally expressed as flame resistant in previous NFPA editions.
• Required Level of Personal Protection Equipment (PPE). Arc rating of PPE should correspond with the appropriate hazard level and incident energy present.
• Highest Hazard/Risk Category (HRC) for the equipment. Hazard/risk categories ranges from 0-4 and helps indicate arc rating, appropriate PPE and clothing requirements.

2. At Nominal System Voltage:

This identifies the voltage by which the electrical system is designated, to which certain operating characteristics are related and near the voltage level at which the system operates. Generally, it is about five to ten percent below the maximum system voltage for which system components are designed. Nominal system voltage is measure in volts.

3. Arc Flash Boundary

The Arc Flash Boundary identifies systems of 50 volts and greater where the distance at which the incident energy level equals 1.2 cal/cm2. This must be identified on a label because this incident energy distance can result in a second degree burn if skin is unprotected. There are three different types of approaches for arc flash boundaries.

• Limited Approach Boundary – approach that identifies distance from exposed energized electrical conductor or circuit part in which a shock hazard exists.
• Prohibited Approach Boundary – approach that identifies distance from exposed energized electrical conductor or circuit part in which work is considered the same as making contact with the electrical conductor or circuit part.
• Restricted Approach Boundary – approach that identifies distance from exposed energized electrical conductor or circuit part in which there is an increased risk of shock, due to electrical arc-over combined with inadvertent movement, for personnel working in close proximity.

For the design and label layout, the NFPA and NEC don’t superficially set forth requirements but direct readers to the ANSI/NEMA Z535.4-2011, Product Safety Signs and Labels, for guidelines on the design of warning labels. Thus, it is recommended that the header, message and pictogram, if used, be formatted according to the ANSI standard.

The NFPA and NEC do not specify whether to use a Danger or Warning header, leaving this up to the employer. Some companies use Warning, some Danger. Some use Danger when the voltage is over 600v or when the incident energy is over 40 cals/cm2, and Warning when it is under that threshold. This should be decided by the employer and used consistently throughout the plant.

3.5" x 5" arc flash danger labels

In addition to warning of an arc flash hazard with the appropriate nominal system voltage and arc flash boundary, arc flash labels must instruct employees to wear the proper personal protection equipment or clothing. Many also take the opportunity to inform employees of which Hazard/Risk Category and available incident energy is present. As Brady’s Arc Flash Labels demonstrate all of this information, although not fully required, is presented on a label.

3.5" x 5" arc flash warning labels

Also not required by NFPA or NEC, they may also choose to include a symbol or pictogram. There are no standards for how an arc flash pictogram should appear. These examples show the pictogram used by Brady on its arc flash labels.

Labels must be able to withstand their usage environment. This means that the print should not fade, and adhesive should be aggressive enough to avoid peeling. The arc flash labels on this page are printed on a durable polyester base that is over-laminated to protect the text and graphics. The back of the labels also employ an acrylic adhesive, which allows the labels to be securely and permanently affixed to a wide range of surfaces.

View Arc Flash labels available from Brady.