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ELECTRICAL SAFETY

This certificate program covers the basics of electrical safety, including current, voltage, and ohm definitions, hazards related to electricity, preventive measures, statutory requirements, and safe usage considerations. It also explores electrical installations, components, hazards, and the principles of electrical safety.

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ELECTRICAL SAFETY

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  1. ELECTRICAL SAFETY Safety and Health Officer Certificate Programme

  2. Session/LessonPlans

  3. OBJECTIVES • Statethedefinitionofcurrent,voltandohm • Explain4hazardsrelatedtoelectricity • Explain2basicpreventivemeasuresinelectricalsafety

  4. OBJECTIVES • Stateatleast4considerationsinthesafeuseofelectricity • Identifystatutoryrequirementsrelatedtoelectricalsafety

  5. SCOPE • Definition • Electricalinstallation • Hazardandeffectsof electriccurrents • Principles of electrical safety • Safeuse of electricity • Electricalsafetycontrols • Conclusion

  6. ELECTRICITY • Aformof energythatisefficient andsimple • Usages: • Lighting • Heating • Energyuse (ovenetc)

  7. TERMINOLOGY • Electricisaformofenergy that is • producedfromtheflowofelectrons. • Itisageneraltermthatincludesenergy relatedtoelectricitycharges,whetherstatic ordynamic.

  8. FACTORS THAT INFLUENCE ELECTRICITY • Volt • Theforceofelectricenergy • Ampere • Actualflowof electricity • Ohm • Characteristicforthecircuit orrouteofwhich electricityflows andoffersresistancetothecurrent

  9. ADVANTAGES OF ELECTRICITY • Cost effective • Clean • Easytouse • Doesnotrequirestorage

  10. CHARACTERISTICS OF ELECTRICITY • Cannotbeseen • Cannotbeheard • Cannotbesmelt

  11. ELECTRICAL INSTALLATIONS • Includes: • Circuit • Conductor • Mainswitch,localanddistributingboard • Circuitbreakers • Fuse • Socketandplug

  12. ELECTRICAL INSTALLATIONS - CIRCUIT • Whereelectriccurrent flows • Providesthesource of energy • Is complementedbyuse of aconductorto allowcontrol of current

  13. ELECTRICAL INSTALLATIONS - CONDUCTOR • Comprisesof: • Internally:Metal whichallowstheflow ofelectricity • Externally:Rubber– forinsulation

  14. ELECTRICAL INSTALLATIONS - MAIN SWITCH, LOCAL & DISTIBUTION BOARD • Mainswitchfunctionsasasourceofelectriccurrent and distributes itto other parts according to requirements • Functionstostoptheflowofelectricitycurrentinthe circuit • Distribution board comprises ofmain switch,circuit breaker and other switches.Itreceives electric currentexternallybefore distribution.

  15. ELECTRICAL INSTALLATIONS - CIRCUIT BREAKERS • Functionswhenthereis overloadof electricity • Prevents overloadof excess heat that may cause combustion • Closedswitch • Ithasanautomaticswitchwhichretractsfromthe ‘on’positionto ‘off’positionwhenthere is an overloadofelectricityflowin thecircuit

  16. ELECTRICAL INSTALLATIONS - FUSE • Apiece of thinmetalthatwill melt ata level belowoverloadleveltobreakthecircuit • Stopstheflow of electricity

  17. ELECTRICAL INSTALLATIONS - EXTERNAL SOCKET Entrytothecircuitandallowstappingtolet electricityflowtotheequipmentrequiringit.

  18. ELECTRICAL INSTALLATIONS - PLUG Isconnectedtoaflexiblecablethatsupplies electricitytotheequipment,andisinserted intotheexternalsockettocompleteanother circuit.

  19. ELECTRICAL HAZARDS • Electricshock • Lighting • Fire • Electrostatic

  20. ELECTRICAL HAZARDS - ELECTRIC SHOCK • Usuallyfromalivewiretoearth • Makesthemusclesshortenandspasm • Mayaffect heartreactions • Mayresultinrespiratoryfailure

  21. ELECTRICAL HAZARDS - LIGHTING • ArcEyes • Fromultravioletlightswhenlookingatelectricarc orweldingflash • Symptomssimilar toconjunctivitis • Situationmaycontinuefor3 to4 days • Doesnotaffectcontactlens 20

  22. ELECTRICAL HAZARDS - FIRE equipment charges. orrelease ofelectrostatic

  23. ELECTRICAL HAZARDS ELECTROSTATIC • Results thatis produced by electricity charges trappedinisolators.Thechargesmaybedistributed insideoroutsideobjectsthathavebeenisolatedor itmay concentrate on conductors thathave been earthed • Highvoltage,lowcurrent • Effectofelectric shock and ignition sources in a highlyflammableenvironment,if chargesare high

  24. ELECTRICAL SAFETY • Theeffectsofelectriccurrentdifferaccordingto: • Age • Gender • Bodyresistance • Healthlevel

  25. HOW ELECTRICITY FLOWS IN THE BODY Highpain Moderatepain Toearth Toearth HANDTOFEET HANDTOHAND 24 Copyright@NIOSH2005

  26. EFFECTS OF ELECTRICITY • Dependson: • Theamountof currentand voltage • Bodyresistance • Severityofelectricshock • Durationofcurrentflow

  27. OHM LAW Current(I):Volt(V) Resistance(R) Orusetheactualmeasurement: Amperes: Volt Ohm

  28. OHM LAW EXAMPLE Forelectricshockeffects valueofdanger 27

  29. EFFECTS OF ELECTRICITY NationalSafetyCouncil-Indus.Safety&Healthmgmtbook Current(mAmps) Effectstohuman 3 milliamps Mildshock 7milliamps Painfulelectric shock 20milliamps Difficultybreathing 70milliamps Riskof death 700milliamps Burningofbodytissues 3000milliamps Heartstops

  30. HUMAN BODY RESISTANCE TO ELECTRICITY FLOW TYPESOFRESISTANCE Dry humanskin Wethumanskin Internalbody -Handto feet Internalbody -Earto ear VALUE 100,000-600,000ohms Approx.1,000Ohm 400-800ohms Approx.100ohms

  31. VOLTAGE SHOCK THRESHOLD AT 50 Hz

  32. PRINCIPLES OF ELECTRICAL SAFETY Mainobjective: Protectpeoplefromelectricshock, fireandeffects of burnsduetocontactwithelectricity

  33. PRINCIPLES OF ELECTRICAL SAFETY • Twobasicpreventionsteps: • Protectionfromdirectcontact • Protectionfromindirectcontact

  34. PRINCIPLES OF ELECTRICAL SAFETY • Protectionfromdirectcontact • Providesisolationtoparts ofequipmentsthathas potentialto release charges • Protectionfromindirectcontact • Provideseffective earthingto isolatemetals that canchargeelectricityincaseoffailureofthe mainisolator

  35. SAFE USE OF ELECTRICITY • Considerations: • Circuitprotector • Isolatingswitch • Equipmentmaintenanceandrepair • Earthing • Protection

  36. SAFE USE OF ELECTRICITY CIRCUIT PROTECTOR • Allelectricequipmentsusedmusthavea fuseandcircuit breakerthat issuitable topreventitfrom overloading.

  37. SAFE USE OF ELECTRICITY - ISOLATING SWITCH • Labeled • Easyreachablefromthefloor • Is attachedtoeachindividualmachinery • Possesssafetylockwhenin‘off’ position

  38. SAFE USE OF ELECTRICITY EQUIPMENT MAINTENANCE & REPAIR • Preparesafeworkproceduresfor maintenanceworks • Preparerulesandconductinspection/ monitoring • Prepareamaintenanceprogramme/ schedule

  39. SAFE USE OF ELECTRICITY EQUIPMENT MAINTENANCE & REPAIR • Prepareaccessaroundtheequipmentto alloweasymaintenanceandrepair • Worksdonebyacompetenttechnician • Ensuresuitablereplacement of components such asfuse,capacitors

  40. SAFE USE OF ELECTRICITY - EARTHING • Forallelectrical items • Circuit isconnecteddirect,not througha switch

  41. SAFE USE OF ELECTRICITY - PROTECTION • Provideforearthleakageprotectionsuchas Residual CurrentDevices • Haveanemergencystopswitch,interlock switch • Isolatetheconductor • Displayappropriatewarningsignages

  42. ELECTRICAL SAFETY CONTROLS • Governmentcontrols: • Provisionof Regulationsandenforcement • ElectricitySupplyAct1990 • ElectricitySupplyRegulations1994 • SIRIM Standards • OccupationalSafetyandHealth Act1994(OSHA 1994)

  43. ELECTRICAL SAFETY CONTROLS • OCCUPATIONALSAFETYANDHEALTHACT1994 • Employers: • Havesafe systemofwork(SOP) • Providetraining,informationandinstruction • Providepreventionmeasures andprotectiontoworkers andcontractors

  44. ELECTRICAL SAFETY CONTROLS • OCCUPATIONALSAFETYANDHEALTHACT1994 • Manufacturers,suppliers,designers: • Conducttestingandinspectionto ensureuser safety • Workers: • Complytoall rules andregulationsissued bythe employer

  45. CONCLUSION • Electricitymayresultinmultiplehazardsthatmay affectworker safetyandhealth • Therearetwobasicpreventionmeasuresthatmay betaken toprotectagainstelectricalhazards • Thesearefollowedelectricalsafetymeasuresasdiscussed • Thegovernmentalsoregulatesthesafeuseofelectricity through the formulationandenforcement ofvariousregulations 44

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