A recent survey conducted by Littelfuse, Inc. reveals that arc-flash safety is a priority among plant professionals. It showed that protection technologies such as arc-flash relays are rapidly growing in popularity.
Even 10 years ago, arc-flash danger didn't demand the attention it does today. Today 85% of the 825 survey respondents agree or strongly agree that arc-flash mitigation is important. According to the Occupational Safety & Health Administration, industrial arc-flash events cause approximately 80% of electrically related accidents and fatalities among qualified electrical workers.
As of late awareness has greatly increased and plant managers and company leaders are taking action. The majority of industrial professionals surveyed (67%) reported completing an arc-flash hazard assessment in their facilities.
Arc-flash hazard assessments have been used to determine the Hazard Risk Category (HRC) of each piece of electrical equipment (a scale of 1-4). Although the NFPA 70E is moving away from HRCs, they remain a well-known classification. More than 50% of survey respondents reported having significant (HRC 3 or higher) arc-flash hazards and agreed that reducing those hazards is important.
The question is, how to reduce arc-flash hazards and keep workers safe? Survey respondents ranked the popularity of solutions, with arc-flash relays standing out as relative newcomers that are being rapidly embraced.
The most popular mitigation technique is current-limiting fuses, followed by arc-resistant switchgear, arc-flash relays, and high-resistance grounding. Current-limiting fuses are well established in the industry, but because an arc-flash draws less current than a bolted fault and may not be interrupted by the circuit-breaker in its instantaneous operating time, other forms of arc-flash mitigation must be used.
Another option is Arc-resistant switchgear. This can be a costly solution, however, to implement in existing facilities and offers little additional protection when a door is open. High-resistance grounding systems lower the energy available to ground faults and therefore eliminate the occurrence of phase-to-ground arc faults. Phase-to-phase arc faults or phase-to-phase-through-ground arc faults can still occur in high-resistance grounded systems requiring additional mitigation techniques. need to be implemented to lower incident energy. Arc-flash relays stand out as relative newcomers that are being rapidly embraced. Arc-flash relays are a growing solution because they immediately detect the light from an arc and send a trip signal to the circuit breaker to disconnect the power quickly enough to drastically reduce incident energy.
Jeff Glenney, P.Eng., sales engineering manager, of Littelfuse said that as the industry changes slowly, the adoption of this new technology has been quite remarkable.
"Companies feel pressure to reduce arc-flash hazards. Arc-flash relays are easy to install, comparably low cost, and offer simple yet reliable operation," Glenney said. "The fast adoption of arc flash relays and other mitigating techniques will have a significant impact in improving plant worker electrical safety," Glenney said.
The use of these and other devices on circuit-breakers rated 1200 amps or more is now included in the 2014 edition of the NEC, section 240.87 (B).
To read a white paper based on the survey, visit here.
For more information on the Littelfuse PGR-8800 Arc-Flash Relay, visit here.