Cable and Wiring

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1、chapter6BasicelectricalcircuitryandapplicationsUnit2Outcome3Theprimaryroleofanelectricianistheinstallationofelectricalcircuitsandapplications.Inordertoinstallanytypeofapplication,however,itisvitalthatfromthestartofyourcareeryouareabletoputtogetherbasiccircuitry.Thisre

2、quiresknowledgeofallpartsoftheelectricalcircuit,fromthesourceofsupplytotheload.Thischapterwillcoverthevariouswiringsystems,enclosuresandequipmentyouwillneedtobecomefamiliarwithinordertocarryoutyourworkasanelectrician.Wehavelookedatanumberofthetermscoveredinthischapter

3、earlierinthisbook.Earthingandbonding,conductionandshockprotectionallhaveimportantrolestoplayinunderstandingbasiccircuitry,anditisthesefactorsyouwillhavetorememberwhenassemblinganypieceofelectricalequipment.Oncompletionofthischapterthecandidatewillbeableto:•statethecom

4、ponentpartsofanelectricalcircuit•determineappropriatewiringsystems•statethecomponentelementsofelectricalcables•differentiatebetweenearthingandbonding•listpossibleconductivepartsofstructures•statethepurposeandfunctionofearthprotection•listbasicprinciplesorshockprotecti

5、on,circuitoverloadandshort-circuitprotection.119NVQ2ElectricalInstallationsThecomponentpartsofanelectricalcircuitOncompletionofthistopicareathecandidatewillbeabletostatethecomponentpartsofanelectriccircuit.BS7671definesacircuitas‘anassemblyofelectricalequipmentsupplie

6、dfromObjbj_boPqofkdqfba^olrka^cfkdbo+thesameoriginandprotectedagainstovercurrentbythesameprotectivedevices’.+Sowhatdoesmakeupthecircuit?SourceofsupplyOftenacircuitisthoughtofasbeingtheloadandtheconductorssupplyingtheload.RememberHoweverinrealitytheyareonlypartoft

7、hecircuit.Inorderforcurrenttoflowtwoconditionshavetobemet.Ifad.c.supplyrequiresa1.Therehastobeapotentialdifferenceappliedacrossthecircuit(voltage).highervoltage,aseriesObjbj_boofbatteriescanbeused2.Therehastobeacompletecircuit(circle)forcurrenttoflowaround.Pqofkdqfb

8、a^olrka^cfkdbo++ratherthanjustoneThesourceofsupplycanbea.c.ord.c.Ifad.c.supplyisrequired,thenthisisderivedfromabattery.Fo