Electrical-Safety-Traini教学讲解课件

WorkplaceElectricalSafetyTraining

BIDMCEOC64andEOC17PolicyAteachinghospitalofHarvardMedicalSchool1BIDMCEH&SDepartmentElectricity-TheDangersAbout5workersareelectrocutedeveryweekCauses12%ofyoungworkerworkplacedeathsTakesverylittleelectricitytocauseharmSignificantriskofcausingfires2BIDMCEH&SDepartmentSafetyRequirementsforElectriciansvideo

(Clickonboxtoplayvideo)3BIDMCEH&SDepartmentElectricity–HowitWorksElectricityistheflowofenergyfromoneplacetoanotherRequiresasourceofpower:usuallyageneratingstationAflowofelectrons(current)travelsthroughaconductorTravelsinaclosedcircuit4BIDMCEH&SDepartmentElectricalTermsCurrent--electricalmovement(measuredinamps)Circuit--completepathofthecurrent.Includeselectricitysource,aconductor,andtheoutputdeviceorload(suchasalamp,tool,orheater)Resistance--restrictiontoelectricalflowConductors–substances,likemetals,withlittleresistancetoelectricitythatallowelectricitytoflowGrounding–aconductiveconnectiontotheearthwhichactsasaprotectivemeasureInsulators--substanceswithhighresistancetoelectricitylikeglass,porcelain,plastic,anddrywoodthatpreventelectricityfromgettingtounwantedareas5BIDMCEH&SDepartmentElectricalInjuriesTherearefourmaintypesofelectricalinjuries:Direct:ElectrocutionordeathduetoelectricalshockElectricalshockBurnsIndirect-Falls6BIDMCEH&SDepartmentElectricalShockAnelectricalshockisreceivedwhenelectricalcurrentpassesthroughthebody.Youwillgetanelectricalshockifapartofyourbodycompletesanelectricalcircuitby…Touchingalivewireandanelectricalground,orTouchingalivewireandanotherwireatadifferentvoltage.7BIDMCEH&SDepartmentShockSeveritySeverityoftheshockdependson:PathofcurrentthroughthebodyAmountofcurrentflowingthroughthebody(amps)Durationoftheshockingcurrentthroughthebody,

LOWVOLTAGEDOESNOTMEANLOWHAZARD8BIDMCEH&SDepartmentDangersofElectricalShockCurrentsabove10mA*canparalyzeor“freeze”muscles.Currentsmorethan75mAcancausearapid,ineffectiveheartbeat--deathwilloccurinafewminutesunlessadefibrillatorisused75mAisnotmuchcurrent–asmallpowerdrilluses30timesasmuch*mA=milliampere=1/1,000ofanampereDefibrillatorinuse9BIDMCEH&SDepartmentBurnsMostcommonshock-relatedinjuryOccurswhenyoutouchelectricalwiringorequipmentthatisimproperlyusedormaintainedTypicallyoccursonhandsVeryseriousinjurythatneedsimmediateattention10BIDMCEH&SDepartmentFallsElectricshockcanalsocauseindirectinjuriesWorkersinelevatedlocationswhoexperienceashockmayfall,resultinginseriousinjuryordeath11BIDMCEH&SDepartmentElectricalHazardsandHowto

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Electricalaccidentsarecausedbyacombinationofthreefactors:Unsafeequipmentand/orinstallation,Workplacesmadeunsafebytheenvironment,andUnsafeworkpractices.12BIDMCEH&SDepartmentHazard–ExposedElectricalPartsCoverremovedfromwiringorbreakerbox13BIDMCEH&SDepartmentControl–IsolateElectricalPartsUseguardsorbarriersReplacecoversGuardlivepartsofelectricequipmentoperatingat50voltsormoreagainstaccidentalcontact14BIDMCEH&SDepartmentControl–IsolateElectricalParts-Cabinets,Boxes&Fittings

Conductorsgoingintothemmustbeprotected,andunusedopeningsmustbeclosed15BIDMCEH&SDepartmentControl–CloseOpeningsJunctionboxes,pullboxesandfittingsmusthaveapprovedcoversUnusedopeningsincabinets,boxesandfittingsmustbeclosed(nomissingknockouts)Photoshowsviolationsofthesetworequirements16BIDMCEH&SDepartmentHazard-OverheadPowerLinesUsuallynotinsulatedExamplesofequipmentthatcancontactpowerlines:CraneLadderScaffoldBackhoeScissorsliftRaiseddumptruckbedAluminumpaintroller17BIDMCEH&SDepartmentControl-OverheadPowerLinesStayatleast10feetawayPostwarningsignsAssumethatlinesareenergizedUsewoodorfiberglassladders,notmetalPowerlineworkersneedspecialtraining&PPE18BIDMCEH&SDepartmentHazard-InadequateWiringHazard-wiretoosmallforthecurrentExample-portabletoolwithanextensioncordthathasawiretoosmallforthetoolThetoolwilldrawmorecurrentthanthecordcanhandle,causingoverheatingandapossiblefirewithouttrippingthecircuitbreakerThecircuitbreakercouldbetherightsizeforthecircuitbutnotforthesmaller-wireextensioncordWireGaugeWIREWiregaugemeasureswiresranginginsizefromnumber36to0Americanwiregauge(AWG)19BIDMCEH&SDepartmentControl–UsetheCorrectWireWireuseddependsonoperation,buildingmaterials,electricalload,andenvironmentalfactorsUsefixedcordsratherthanflexiblecordsUsethecorrectextensioncordMustbe3-wiretypeanddesignedforhardorextra-harduse20BIDMCEH&SDepartmentHazard–DefectiveCords&WiresPlasticorrubbercoveringismissingDamagedextensioncords&tools21BIDMCEH&SDepartmentHazard–DamagedCordsCordscanbedamagedby:AgingDoororwindowedgesStaplesorfasteningsAbrasionfromadjacentmaterialsActivityintheareaImproperusecancauseshocks,burnsorfire22BIDMCEH&SDepartmentControl–Cords&WiresInsulatelivewiresCheckbeforeuseUseonlycordsthatare3-wiretypeUseonlycordsmarkedforhardorextra-hardusageUseonlycords,connectiondevices,andfittingsequippedwithstrainreliefRemovecordsbypullingontheplugs,notthecordsCordsnotmarkedforhardorextra-harduse,orwhichhavebeenmodified,mustbetakenoutofserviceimmediately23BIDMCEH&SDepartmentPermissibleUseofFlexibleCordsStationaryequipment-tofacilitateinterchangeDONOTuseflexiblewiringwherefrequentinspectionwouldbedifficultorwheredamagewouldbelikely.Flexiblecordsmustnotbe...runthroughholesinwalls,ceilings,orfloors;runthroughdoorways,windows,orsimilaropenings(unlessphysicallyprotected);hiddeninwalls,ceilings,floors,conduitorotherraceways.24BIDMCEH&SDepartmentGroundingGroundingcreatesalow-resistancepathfromatooltotheearthtodisperseunwantedcurrent.

Whenashortorlightningoccurs,energyflowstotheground,protectingyoufromelectricalshock,injuryanddeath.25BIDMCEH&SDepartmentHazard–ImproperGroundingToolspluggedintoimproperlygroundedcircuitsmaybecomeenergizedBrokenwireorplugonextensioncordSomeofthemostfrequentlyviolatedOSHAstandards26BIDMCEH&SDepartmentControl–GroundTools&EquipmentGroundpowersupplysystems,electricalcircuits,andelectricalequipmentFrequentlyinspectelectricalsystemstoinsurepathtogroundiscontinuousInspectelectricalequipmentbeforeuseDon’tremovegroundprongsfromtoolsorextensioncordsGroundexposedmetalpartsofequipment27BIDMCEH&SDepartmentControl–UseGFCI(ground-faultcircuitinterrupter)ProtectsyoufromshockDetectsdifferenceincurrentbetweentheblackandwhitewiresIfgroundfaultdetected,GFCIshutsoffelectricityin1/40thofasecondUseGFCI’sonall120-volt,single-phase,15-and20-amperereceptacles,orhaveanassuredequipmentgroundingconductorprogram.28BIDMCEH&SDepartmentHazard–OverloadedCircuitsHazardsmayresultfrom:Toomanydevicespluggedintoacircuit,causingheatedwiresandpossiblyafireDamagedtoolsoverheatingLackofovercurrentprotectionWireinsulationmelting,whichmaycausearcingandafireintheareawheretheoverloadexists,eveninsideawall29BIDMCEH&SDepartmentControl-ElectricalProtectiveDevicesAutomaticallyopenscircuitifexcesscurrentfromoverloadorground-faultisdetected–shuttingoffelectricityIncludesGFCI’s,fuses,andcircuitbreakersFusesandcircuitbreakersareovercurrentdevices.Whentoomuchcurrent:FusesmeltCircuitbreakerstripopen30BIDMCEH&SDepartmentPowerToolRequirementsHaveathree-wirecordwithgroundpluggedintoagroundedreceptacle,orBedoubleinsulated,orBepoweredbyalow-voltageisolationtransformer31BIDMCEH&SDepartmentToolSafetyTipsUseglovesandappropriatefootwearStoreindryplacewhennotusingDon’tuseinwet/dampconditionsKeepworkingareaswelllitEnsurenotatrippinghazardDon’tcarryatoolbythecordDon’tyankthecordtodisconnectitKeepcordsawayfromheat,oil,&sharpedgesDisconnectwhennotinuseandwhenchangingaccessoriessuchasblades&bitsRemovedamagedtoolsfromuse32BIDMCEH&SDepartmentPreventingElectricalHazards-ToolsInspecttoolsbeforeuseUsetherighttoolcorrectlyProtectyourtoolsUsedoubleinsulatedtoolsDoubleInsulatedmarking33BIDMCEH&SDepartmentTemporaryLights

Protectfromcontactanddamage,anddon’tsuspendbycordsunlessdesignedtodoso.34BIDMCEH&SDepartmentCluesthatElectricalHazardsExistTrippedcircuitbreakersorblownfusesWarmtools,wires,cords,connections,orjunctionboxesGFCIthatshutsoffacircuitWornorfrayedinsulationaroundwireorconnection35BIDMCEH&SDepartmentLockoutandTaggingofCircuitsApplylockstopowersourceafterde-energizingTagdeactivatedcontrolsTagde-energizedequipmentandcircuitsatallpointswheretheycanbeenergizedTagsmustidentifyequipmentorcircuitsbeingworkedon36BIDMCEH&SDepartmentSafety-RelatedWorkPractices

Toprotectworkersfromelectricalshock:UsebarriersandguardstopreventpassagethroughareasofexposedenergizedequipmentPre-planwork,posthazardwarningsanduseprotectivemeasuresKeepworkingspacesandwalkwaysclearofcords37BIDMCEH&SDepartmentSafety-RelatedWorkPracticesUsespecialinsulatedtoolswhenworkingonfuseswithenergizedterminalsDon’tusewornorfrayedcordsandcablesDon’tfastenextensioncordswithstaples,hangfromnails,orsuspendbywire.38BIDMCEH&SDepartmentPreventingElectricalHazards-PlanningPlanyourworkwithothersPlantoavoidfallsPlantolock-outandtag-outequipmentRemovejewelryAvoidwetconditionsandoverheadpowerlines39BIDMCEH&SDepartmentAvoidWetConditionsIfyoutouchalivewireorotherelectricalcomponentwhilestandinginevenasmallpuddleofwateryou’llgetashock.Damagedinsulation,equipment,ortoolscanexposeyoutoliveelectricalparts.Improperlygroundedmetalswitchplates&ceilinglightsareespeciallyhazardousinwetconditions.Wetclothing,highhumidity,andperspirationincreaseyourchancesofbeingelectrocuted.40BIDMCEH&SDepartmentPreventingElectricalHazards-PPEProperfootprotection(nottennisshoes)Rubberinsulatinggloves,hoods,sleeves,matting,andblankets

Hardhat(insulated-nonconductive)41BIDMCEH&SDepartmentPreventingElectricalHazards–ProperWiringandConnectorsUseandtestGFCI’sCheckswitchesandinsulationUsethreeprongplugsUseextensioncordsonlywhennecessary&assureinproperconditionandrighttypeforjobUsecor