Download - Arc Flash Approach Boundaries - ITU Arc Flash Safetyarcflashengineering.com/downloads/Approach_Boundaries.pdfArc Flash Boundary • The qualified worker must insure that no one is

Arc Flash Approach BoundariesLimited Approach Boundary• AnyonewithinthisareaissubjecttoinjuryshouldanArcFlashoccur.• Thequalifiedworkermustinsurenooneisallowedinthisareawhencoversare

removed.• Heatenergywithinthisareacouldcausegreaterthanseconddegreeburns.• ProperPPEmustbewornbyallpeopleinthisarea• Unqualifiedpeoplemaybethisclosewhensupervisedbyaqualifiedelectrician.

Restricted Approach Boundary• AnyonewithinthisareaissubjecttoinjuryshouldanArcFlashoccur.• Thequalifiedworkermustinsurenooneisallowedinthisareawhencoversare

removed.• Heatenergywithinthisareacouldcausegreaterthanseconddegreeburns.• ProperPPEmustbewornbyallpeoplewithinthisdistance.• Unqualifiedarenotallowedwithinthisdistance.• Voltageprotectionsuchasvoltageratedtoolsandglovesmustbeappliedwithinthis

distance.

Prohibited Approach Boundary• AnyonewithinthisareaissubjecttoinjuryshouldanArcFlashoccur.• Thequalifiedworkermustinsurenooneisallowedinthisareawhencoversare

removed.• Heatenergywithinthisareacouldcausegreaterthanseconddegreeburns.• ProperPPEmustbewornbyallpeoplewithinthisdistance.• Unqualifiedarenotallowedwithinthisdistance.• Voltageprotectionsuchasvoltageratedtoolsandglovesmustbeappliedwithinthis

distance.

Arc Flash Boundary• Thequalifiedworkermustinsurethatnooneisallowedinthisareawhencoversare

removed.• AnyonewithinthisareaissubjecttoinjuryordeathshouldanArcFlashoccur.• Heatenergywithinthisareacouldcausegreaterthanseconddegreeburns.• Theintenseheatwillvaporizemetalproducinggases,vapors,andmoltenshrapnel.• Thesegasesexpandrapidlyupto67,000timestheoriginalspaceoccupiedbythe

metal.ThisexplosionisroughlyequivalenttothedetenationpropertiesofTNT.• Thesoundwavecanexceed160db.

Barricadesshallbeusedinconjunctionwithsafetysignswhereitisnecessarytopreventorlimitemployeeaccesstoworkareascontainingenergizedconductorsorcircuitsparts.Conductivebarricadesshallnotbeusedwhereitmightcauseanelectricalhazard.Barricadesshallbeplacednocloserthanthelimitedapproachboundarygiveninthetable:NFPA70E2012EditionTable130.4(C)(a)andTable130.4(C)(b)