More than 1,000 workers in food plants and other industrial workplaces are injured and hundreds killed from electrical shocks each year, data from the U.S. Department of Labor's Bureau of Labor Statistics suggest. Ground fault circuit interrupters (GFCI) could mitigate the danger from electrically powered equipment, but residential GFCI devices trip at 6 Milliamperes (mA), too low a threshold for industrial use.
Fortunately, UL has created a standard for industrial GFCI. The first GFCI to meet UL 943C requirements debuted this week when Cincinnati-based Littelfuse Inc. announced the availability of its SB6100 series, which trips at 20 mA. The devices, which can be machine mounted or attached adjacent to an electric cabinet in its own enclosure, have voltage ratings in the 208-600 V range and are rated at 100 A.
"Shock remains a major cause of workplace injury," maintains Tony Locker, manager of Littelfuse's protection relays and line of custom electrical products. He cites an OSHA report indicating 1,480 workplace injuries from electric shock occurred in 2007. In 1999, 278 workers were killed by electrocution on the job, based on data from the National Institute for Occupational Safety & Health.
Portable equipment used in washdown areas and other wet environments in food plants is a primary application for the industrial GFCI, Locker says. Mixers, fans and other electrical equipment used in food & beverage processing also could benefit.
Since the National Electrical Code was amended in 1973 to require GFCI in washrooms, residential electrocution rates have been cut in half. Electric shock in the workplace has flown below the radar, however, while companies concentrate on identifying and eliminating the potential for arc flash risks. In a March Littelfuse survey involving 825 respondents, 88% of manufacturers rated arc flash mitigation as important or very important, and 77% said they had completed an arc flash hazard assessment on panels in Hazard Risk Categories 3 or larger. Given those awareness and activity levels, Locker believes electric shock prevention is the new frontier in workplace safety.
