![]() Sometimes this boundary is the furthest one from the exposed equipment, other times the limited approach boundary is the furthest out. That’s the distance where a worker without appropriate PPE would receive second-degree burns. The arc flash boundary is calculated to 1.2 calories/cm2 of incident energy. The arc flash boundary, or restricted approach boundary, changes depending on the potential arc flash hazard. But unique solutions exist IF you have done arc flash engineering studies and have a properly written electrical safety program, a knowledgeable arc flash risk assessment, an effective arc flash training program and a robust electrical safety work practice audit.Į-Hazard still supports using ARC 4 cal/cm² minimum PPE for all 480V equipment operation other than operation of contactors.Arc Flash Levels of Protection are best understood as layers or boundaries of protection around and away from hazardous electrical equipment. For electricians, the use of AR PPE daily wear is still the most effective and least costly solution to compliance. These types of solutions can really make AR PPE reasonable and less costly for operators. If the AFB is 1 foot and the equipment can be operated from the side, the AF PPE could be something as simple as an Arc-Rated sleeve and glove for the hand in the AFB. So if the AFB is 2 inches, a leather glove or an arc rated glove with an Arc Rating of greater than the calculated hazard at the location of the hand inches (likely less than 1 cal/cm²) would be all the PPE required. Do be sure all maintenance has been done on upstream protective devices and on the disconnect itself or the risk is more than the calculated energy. By calculating, you know these are not the “horrible” disconnects (we have calculated disconnects at over 40 cal/cm². You must do your due diligence of an adequate risk assessment but outside the AFB, there are no PPE requirements. There is still language about natural fibers under AF gear but the requirements are gone in the new 2015 version of the standard IF you are outside the AFB. The idea would be that you wear AF PPE inside the boundary but outside the boundary, nothing is required. Would a long sleeve shirt still be required for throwing the disconnects on those lower risk machines?Ī. We have arc flash analysis done on our equipment, and some of the calculated boundaries are only a couple inches or less. For a 480v machine panel disconnect, Table 130.7(C)(15)(a) lists the potential boundary at 30”. It is my understanding this has to be worn inside of the arc flash boundary (AFB). According to NFPA 70E Table 130.7(C)(16), an HRC 0 requires a long sleeve shirt.
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