Arc Flash Warning Labels
Arc flash warning labels on hazardous equipment are required by NEC Section 110.16 and by NFPA 70E. The following requirements apply:
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- All hazardous equipment installed or modified after 2002 is required to carry a warning label. NEC 110.16 specifically mentions "switchboards, panel boards, industrial control panels and motor control centers that ... are likely to require examination, adjustment, servicing, or maintenance while energized." Many companies choose to mark additional equipment for maximum safety.
- Equipment must be marked in the field, rather than by the equipment manufacturer or installer. Arc flash hazard varies depending on actual operating conditions, including upcurrent protective devices and voltage. Labeling is the responsibility of the company operating the equipment.
- Labels must be placed and sized so as to be visible to personnel before beginning maintenance or
inspection.
- NFPA 70E 2009 requires that one of two specific pieces of information appear on arc flash labels: available incident energy or required level of PPE. These values are determined by an arc flash hazard analysis, and need to be calculated separately for each piece of equipment labeled. This is a new requirement. Previous versions of the code did not specify what information should appear on labels.
- NFPA 70E 2009 requires that all arc flash analysis be reviewed at least every five years to "account for changes in the electrical distribution system that could affect the results of the arc flash hazard analysis." Although this does not require changes in arc flash labels, some consultants are recommending that the date of the arc flash analysis be included on the each label.
Arc Flash Label Design
 No standards for the design of arc flash labels are currently specified by law. However, the NFPA recommends following ANSI Z535.4-1998, which offers two options for signal words and colors:
- The signal word DANGER, which appears in white letters on a red background, signifies the
most serious threats. It should not be used throughout a facility, but only in cases of extreme
danger. A guideline is to use DANGER where incident energy is above 40 cal/cm2, which is the
highest energy for which PPE is considered effective.
- The signal word WARNING, appearing in black letters on an orange background, is appropriate for
use in any instance where a hazard could cause death or serious injury.
We recommend that arc flash warning labels carry additional information beyond what is required by law, so that workers can have all the relevant information to make informed choices for safety procedures. Appropriate information may include assumed working distance; flash protection boundary; and limited, restricted, and prohibited approach boundaries. It is important to strike a balance in providing information. Too little information can leave workers unaware of risks, while too much may make labels confusing or hard to read.
A number of printers for creating custom arc flash labels are available. Some of these devices can be found on our Other Resources page. Use the link below for information about the DuraLabel PRO arc flash labeling package special.
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