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Electric Power Standards- What does OSHA consider reasonable estimates of available heat energy?

arc flashWhat does OSHA consider reasonable estimates of available heat energy? Understanding that the largest available amount of fault current does not necessarily translate into the highest levels of available heat energy is extremely important. Device clearing times plays an important factor when determining reasonable estimates. An electric power system could have system locations with small amounts of fault current and large clearing time which could equate to to large amounts of available heat energy. Many utilities are looking throughout their system to determine if locations are fully protected by adding Hot Line Tag devices which clear instantaneously, 3 cycles or less. This requires utilities to have a strict Hot Line Tag procedure in place to ensure all work performed on or near electric power lines and equipment has been placed in a Hot Line Tag position. Note the compliance date has been extended to April 1, 2015 for completion of estimates of available heat energy exposures faced by employees who are exposed to electric arc hazards. Appendix E located in 29 CFR 1910.269 and 29 CFR Subpart V outlines methodology to comply with the standards. For more information contact us at SET Solutions, LLC. 

Electric Power, osha