What is NEC?
110.16 Flash Protection. Switchboards, panelboards, industrial control panels, and motor control centers in other than dwelling occupancies, that 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.
This requirement excludes electrical equipment in dwelling units. But for all other electrical equipment where a worker might perform tasks that could place him or her at risk, it requires that a label be affixed warning of the potential for an arc flash hazard. This encompasses most industrial and commercial electrical equipment since equipment that is being checked for voltage during the lockout/tagout procedure for putting equipment into a “safe working condition” is considered “live”.
This requirement is intended to reduce the occurrence of serious injury or death due to arcing faults for workers who work on or near energized electrical equipment. The warning label should remind a qualified worker who intends to open the equipment for analysis or work that a serious hazard exists and that the worker should follow work practices and wear personal protection equipment (PPE) for the specific hazard (a non qualified worker must not be opening the equipment).