Written by Steve Hudgik
The National Fire Protection Agency (NFPA) developed NFPA 70, known as the National Electric Code (NEC), as a standard for the design and installation of electrical systems in the U.S. Compliance with the NEC is mandated by OSHA.
The NEC refers to arc flash in Section 110.16, which reads, "Flash Protection. Switchboards, panel boards, industrial control panels, meter socket enclosures, and motor control centers in other than dwelling occupancies, which are likely to require examination, adjustment, servicing, or maintenance while energized, shall be field marked to warn qualified persons of potential electric arc flash hazards*. The marking shall be located so as to be clearly visible to qualified persons before examination, adjustment, servicing, or maintenance of the equipment."
The NEC labeling requirements apply to any electrical equipment installed or modified after 2002.
A fine-print note to Section 110.16 suggests that warning label design should comply with ANSI Z535.4, which specifies colors and signal words to be used. This design requirement is not mandatory, but is a good guideline for consistency and visibility of warning labels.