Slide 1

Electrical installation handbookVolume 21SDC010001D0202ABB SACEElectrical devicesnd

Electrical installation handbook

Volume 2

Electrical devices2nd editionFebruary 2004First edition 2003Second edition 2004Published by ABB SACEvia Baioni, 35 - 24123 Bergamo (Italy)All rights reserved1ABB SACE - Electrical devicesIndex

Introduction ..............................................................................................2

1 Standards1.1 General aspects..............................................................................31.2 IEC Standards for electrical installation..........................................152 Protection of feeders2.1 Introduction...................................................................................222.2 Installation and dimensioning of cables .........................................252.2.1 Current carrying capacity and methods of installation ..........25Installation not buried in the ground .....................................31Installation in ground............................................................442.2.2 Voltage drop ........................................................................562.2.3 Joule-effect losses ...............................................................662.3 Protection against overload...........................................................672.4 Protection against short-circuit......................................................702.5 Neutral and protective conductors ................................................782.6 Busbar trunking systems...............................................................863 Protection of electrical equipment3.1 Protection and switching of lighting circuits .................................1013.2 Protection and switching of generators .......................................1103.3 Protection and switching of motors .............................................1153.4 Protection and switching of transformers ....................................1314 Power factor correction4.1 General aspects..........................................................................1464.2 Power factor correction method..................................................1524.3 Circuit-breakers for the protection andswiching of capacitor banks........................................................1595 Protection of human beings5.1 General aspects: effects of current on human beings ..................1625.2 Distribution systems....................................................................1655.3 Protection against both direct and indirect contact......................1685.4 TT system ...................................................................................1715.5 TN system ..................................................................................1745.6 IT system ....................................................................................1775.7 Residual current devices .............................................................1795.8 Maximum protected length for the protection of human beings ...182Annex A: Calculation toolsA.1 Slide rules .............................................................................200A.2 DOCWin ...............................................................................205Annex B: Calculation of load current Ib ..............................................209Annex C: Calculation of short-circuit current ...................................213Annex D: Calculation of the coefficient k for the cables..................227Annex E: Main physical quantities andelectrotechnical formulas ...................................................2301.1 General aspectsIn each technical field, and in particular in the electrical sector, a conditionsufficient (even if not necessary) for the realization of plants according to thestatus of the art and a requirement essential to properly meet the demandsof customers and of the community, is the respect of all the relevant laws andtechnical standards.Therefore, a precise knowledge of the standards is the fundamental premisefor a correct approach to the problems of the electrical plants which shall bedesigned in order to guarantee that acceptable safety level which is neverabsolute.

Juridical StandardsThese are all the standards from which derive rules of behavior for the juridicalpersons who are under the sovereignty of that State.

Technical StandardsThese standards are the whole of the prescriptions on the basis of whichmachines, apparatus, materials and the installations should be designed,manufactured and tested so that efficiency and function safety are ensured.The technical standards, published by national and international bodies, arecircumstantially drawn up and can have legal force when this is attributed by alegislative measure.

Application fieldsInternational BodyEuropean BodyElectrotechnics andElectronicsIECCENELECTelecommunications

ITUETSIMechanics, Ergonomicsand SafetyISOCENThis technical collection takes into consideration only the bodies dealing with electrical and electronictechnologies.

IEC International Electrotechnical CommissionThe International Electrotechnical Commission (IEC) was officially founded in1906, with the aim of securing the international co-operation as regardsstandardization and certification in electrical and electronic technologies. Thisassociation is formed by the International Committees of over 40 countries allover the world.The IEC publishes international standards, technical guides and reports whichare the bases or, in any case, a reference of utmost importance for any nationaland European standardization activity.IEC Standards are generally issued in two languages: English and French.In1991theIEChasratifiedco-operationagreementswithCENELEC(Europeanstandardization body), for a common planning of new standardization activitiesand for parallel voting on standard drafts.1 Standards3ABB SACE - Electrical devices2ABB SACE - Electrical devicesIntroductionScope and objectivesThe scope of this electrical installation handbook is to provide the designer anduser of electrical plants with a quick reference, immediate-use working tool.This is not intended to be a theoretical document, nor a technical catalogue,but, in addition to the latter, aims to be of help in the correct definition ofequipment, in numerous practical installation situations.

The dimensioning of an electrical plant requires knowledge of different factorsrelating to, for example, installation utilities, the electrical conductors and othercomponents; this knowledge leads the design engineer to consult numerousdocuments and technical catalogues. This electrical installation handbook,however, aims to supply, in a single document, tables for the quick definition ofthemainparametersofthecomponentsofanelectricalplantandfortheselectionof the protection devices for a wide range of installations. Some applicationexamples are included to aid comprehension of the selection tables.

Electrical installation handbook usersThe electrical installation handbook is a tool which is suitable for all those whoareinterestedinelectricalplants:usefulforinstallersandmaintenancetechniciansthrough brief yet important electrotechnical references, and for sales engineersthrough quick reference selection tables.

Validity of the electrical installation handbookSome tables show approximate values due to the generalization of the selectionprocess, for example those regarding the constructional characteristics ofelectrical machinery. In every case, where possible, correction factors are givenfor actual conditions which may differ from the assumed ones. The tables arealways drawn up conservatively, in favour of safety; for more accuratecalculations,theuseofDOCWinsoftwareisrecommendedforthedimensioningof electrical installations.5ABB SACE - Electrical devices4ABB SACE - Electrical devices1.1 General aspects1 Standards

Low Voltage Directive 73/23/CEE 93/68/CEEThe Low Voltage Directive refers to any electrical equipment designed for useataratedvoltagefrom50to1000Vforalternatingcurrentandfrom75to1500V fordirect current.In particular, it is applicable to any apparatus used for production, conversion,transmission, distribution and use of electrical power, such as machines,transformers, devices, measuring instruments, protection devices and wiringmaterials.The following categories are outside the scope of this Directive:electrical equipment for use in an explosive atmosphere;electrical equipment for radiology and medical purposes;electrical parts for goods and passenger lifts;electrical energy meters;plugs and socket outlets for domestic use;electric fence controllers;radio-electrical interference;specialized electrical equipment, for use on ships, aircraft or railways, whichcomplies with the safety provisions drawn up by international bodies in whichthe Member States participate.

Directive EMC 89/336/EEC (Electromagnetic Compatibility)The Directive on electromagnetic compatibility regards all the electrical andelectronic apparatus as well as systems and installations containing electricaland/or electronic components. In particular, the apparatus covered by thisDirective are divided into the following categories according to theircharacteristics:domestic radio and TV receivers;industrial manufacturing equipment;mobile radio equipment;mobile radio and commercial radio telephone equipment;medical and scientific apparatus;information technology equipment (ITE);domestic appliances and household electronic equipment;aeronautical and marine radio apparatus;educational electronic equipment;telecommunications networks and apparatus;radio and television broadcast transmitters;lights and fluorescent lamps.The apparatus shall be so constructed that:a) theelectromagneticdisturbanceitgeneratesdoesnotexceedalevelallowingradio and telecommunications equipment and other apparatus to operateas intended;b) the apparatus has an adequate level of intrinsic immunity to electromagneticdisturbance to enable it to operate as intended.An apparatus is declared in conformity to the provisions at points a) and b)when the apparatus complies with the harmonized standards relevant to itsproduct family or, in case there arent any, with the general standards.1.1 General aspects1 Standards

CENELEC European Committee for Electrotechnical StandardizationThe European Committee for Electrotechnical Standardization(CENELEC) wasset up in 1973. Presently it comprises 27 countries (Austria, Belgium, CzechRepublic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Portugal, Poland, Slovakia, Slovenia, Spain, Sweden, Switzerland, UnitedKingdom) and cooperates with 8 affiliates (Albania, Bosnia and Herzegovina,Bulgaria,Croatia,Cyprus,Romania,Turkey,Ukraine)whichhavefirstmaintainedthe national documents side by side with the CENELEC ones and then replacedthem with the Harmonized Documents (HD). CENELEC hopes and expectsCyprus to become the 28th members before May 2004.There is a difference between EN Standards and Harmonization Documents(HD): while the first ones have to be accepted at any level and without additionsor modifications in the different countries, the second ones can be amended tomeet particular national requirements.EN Standards are generally issued in three languages: English, French andGerman.From 1991 CENELEC cooperates with the IEC to accelerate the standardspreparation process of International Standards.CENELEC deals with specific subjects, for which standardization is urgentlyrequired.When the study of a specific subject has already been started by the IEC, theEuropean standardization body (CENELEC) can decide to accept or, whenevernecessary, to amend the works already approved by the Internationalstandardization body.

EC DIRECTIVES FOR ELECTRICAL EQUIPMENTAmong its institutional roles, the European Community has the task ofpromulgating directives which must be adopted by the different member statesand then transposed into national law.Onceadopted,thesedirectivescomeintojuridicalforceandbecomeareferencefor manufacturers, installers, and dealers who must fulfill the duties prescribedby law.Directives are based on the following principles: harmonization is limited to essential requirements; only the products which comply with the essential requirements specified bythe directives can be marketed and put into service; the harmonized standards, whose reference numbers are published in theOfficial Journal of the European Communities and which are transposed intothe national standards, are considered in compliance with the essentialrequirements; theapplicabilityoftheharmonizedstandardsorofothertechnicalspecificationsis facultative and manufacturers are free to choose other technical solutionswhich ensure compliance with the essential requirements; a manufacturer can choose among the different conformity evaluation proce-dure provided by the applicable directive.The scope of each directive is to make manufacturers take all the necessarysteps and measures so that the product does not affect the safety and healthof persons, animals and property.

COUNTRYSymbolMarkdesignationApplicability/OrganizationEUROPEMarkofcompliancewiththeharmonizedEuropeanstandardslistedintheENECAgreement.AUSTRALIAASMarkElectricalandnon-electricalproducts.ItguaranteescompliancewithSAA(StandardAssociationofAustralia).AUSTRALIAS.A.A.MarkStandardsAssociationofAustralia(S.A.A.).TheElectricityAuthorityofNewSouthWalesSydneyAustraliaAUSTRIAOVEAustrianTestMarkInstallationequipmentandmaterialsASDC008045F02017ABB SACE - Electrical devices6ABB SACE - Electrical devices1.1 General aspects1 Standards

ABBSACEcircuit-breakers(Isomax-Tmax-Emax)areapprovedbythefollowingshipping registers:RINADNVBVGLLRsABSRegistro Italiano NavaleDet Norske VeritasBureau VeritasGermanischer LloydLloyds Register of ShippingAmerican Bureau of ShippingItalian shipping registerNorwegian shipping registerFrench shipping registerGerman shipping registerBritish shipping registerAmerican shipping registerIt is always advisable to ask ABB SACE as regards the typologies and theperformancesofthecertifiedcircuit-breakersortoconsultthesectioncertificatesin the website http://bol.it.abb.com.

Marks of conformity to the relevant national andinternational StandardsThe international and national marks of conformity are reported in the followingtable, for information only:ManufacturerTechnical fileThe manufacturerdraw up the technicaldocumentationcovering the design,manufacture andoperation of theWhen the CE marking is affixed on a product, it represents a declaration of themanufacturer or of his authorized representative that the product in questionconforms to all the applicable provisions including the conformity assessmentprocedures. This prevents the Member States from limiting the marketing andputting into service of products bearing the CE marking, unless this measure isjustified by the proved non-conformity of the product.

Flow diagram for the conformity assessment procedures established by the Directive73/23/EEC on electrical equipment designed for use within particular voltage range:

EC declaration ofconformityThe manufacturerguarantees and declaresthat his products are inconformitytothetechnicaldocumentationandtothedirective requirementsproduct

Naval type approvalThe environmental conditions which characterize the use of circuit breakers foron-board installations can be different from the service conditions in standardindustrial environments; as a matter of fact, marine applications can requireinstallation under particular conditions, such as:- environments characterized by high temperature and humidity, including salt-mist atmosphere (damp-heat, salt-mist environment);- on board environments (engine room) where the apparatus operate in thepresence of vibrations characterized by considerable amplitude and duration.

In order to ensure the proper function in such environments, the shippingregisters require that the apparatus has to be tested according to specific typeapproval tests, the most significant of which are vibration, dynamic inclination,humidity and dry-heat tests.1.1 General aspects1 Standards

CE conformity markingThe CE conformity marking shall indicate conformity to all the obligationsimposedonthemanufacturer,asregardshisproducts,byvirtueoftheEuropeanCommunity directives providing for the affixing of the CE marking.

COUNTRYSymbolMarkdesignationApplicability/OrganizationAUSTRIAVEIdentificationThreadCablesBELGIUMCEBECMarkInstallationmaterialsandelectricalappliancesBELGIUMCEBECMarkConduitsandducts,conductorsandflexiblecordsBELGIUMCertificationofConformityInstallationmaterialandelectricalappliances(incasetherearenoequivalentnationalstandardsorcriteria)CANADACSAMarkElectricalandnon-electricalproducts.ThismarkguaranteescompliancewithCSA(CanadianStandardAssociation)CHINACCEEMarkGreatWallMarkCommissionforCertificationofElectricalEquipmentCzechRepublicEZUMarkElectrotechnicalTestingInstituteSlovakiaRepublicEVPUMarkElectrotechnicalResearchandDesignInstituteCOUNTRYSymbolMarkdesignationApplicability/OrganizationCROATIAKONKARElectricalEngineeringInstituteDENMARKDEMKOApprovalMarkLowvoltagematerials.Thismarkguaranteesthecomplianceoftheproductwiththerequirements(safety)oftheHeavyCurrentRegulationsFINLANDSafetyMarkoftheElektriskaInspektoratetLowvoltagematerial.Thismarkguaranteesthecomplianceoftheproductwiththerequirements(safety)oftheHeavyCurrentRegulationsFRANCEESCMarkHouseholdappliancesFRANCENFMarkConductorsandcablesConduitsandductingInstallationmaterialsFRANCENFIdentificationThreadCablesFRANCENFMarkPortablemotor-operatedtoolsFRANCENFMarkHouseholdappliances9ABB SACE - Electrical devices1.1 General aspects1 Standards8ABB SACE - Electrical devices1.1 General aspects1 Standards

COUNTRYSymbolMarkdesignationApplicability/OrganizationGERMANYVDEMarkForappliancesandtechnicalequipment,installationaccessoriessuchasplugs,sockets,fuses,wiresandcables,aswellasothercomponents(capacitors,earthingsystems,lampholdersandelectronicdevices)GERMANYVDEIdentificationThreadCablesandcordsGERMANYVDECableMarkForcables,insulatedcords,installationconduitsandductsGERMANYgeprfteSicherheitVDE-GSMarkfortechnicalequipmentSafetymarkfortechnicalequipmenttobeaffixedaftertheproducthasbeentestedandcertifiedbytheVDETestLaboratoryinOffenbach;theconformitymarkisthemarkVDE,whichisgrantedbothtobeusedaloneaswellasincombinationwiththemarkGSHUNGARYMEEIHungarianInstituteforTestingandCertificationofElectricalEquipmentJAPANJISMarkMarkwhichguaranteescompliancewiththerelevantJapaneseIndustrialStandard(s).IRELANDIIRSMarkElectricalequipmentIRELANDCONFOFOI.I.R.S.IIRSMarkElectricalequipmentCOUNTRYSymbolMarkdesignationApplicability/OrganizationITALYIMQMarkMarktobeaffixedonelectricalmaterialfornon-skilledusers;itcertifiescompliancewiththeEuropeanStandard(s).NORWAYNorwegianApprovalMarkMandatorysafetyapprovalforlowvoltagematerialandequipmentNETHERLANDSKEURKEMA-KEURGeneralforallequipmentPOLANDBKWEElectricalproductsRUSSIACertificationofConformityElectricalandnon-electricalproducts.Itguaranteescompliancewithnationalstandard(GosstandardofRussia)SINGAPORESINGAPOROSISIRElectricalandnon-electricalproductsSLOVENIASIQSlovenianInstituteofQualityandMetrologySPAINRMIDADFOAAEEElectricalproducts.ThemarkisunderthecontroloftheAsociacinElectrotcnicaEspaola(SpanishElectrotechnicalAssociation)R O V ED TESTA N D ARPPKMITYC A DE CONNOR MA S U NMARAREDAMR11ABB SACE - Electrical devices1.1 General aspects1 Standards10ABB SACE - Electrical devices1.1 General aspects1 Standards

COUNTRYSymbolMarkdesignationApplicability/OrganizationSPAINAENORAsociacinEspaoladeNormalizacinyCertificacin.(SpanishStandarizationandCertificationAssociation)SWEDENSEMKOMarkMandatorysafetyapprovalforlowvoltagematerialandequipment.SWITZERLANDSafetyMarkSwisslowvoltagematerialsubjecttomandatoryapproval(safety).SWITZERLANDCablessubjecttomandatoryapprovalSWITZERLANDSEVSafetyMarkLowvoltagematerialsubjecttomandatoryapprovalUNITEDKINGDOMASTAMarkMarkwhichguaranteescompliancewiththerelevantBritishStandardsUNITEDKINGDOMBASECMarkMarkwhichguaranteescompliancewiththeBritishStandardsforconductors,cablesandancillaryproducts.UNITEDKINGDOMBASECIdentificationThreadCablesCOUNTRYSymbolMarkdesignationApplicability/OrganizationUNITEDKINGDOMBEABSafetyMarkCompliancewiththeBritishStandardsforhouseholdappliancesUNITEDKINGDOMBSISafetyMarkCompliancewiththeBritishStandardsUNITEDKINGDOMBRITISHTOBEABKitemarkCompliancewiththerelevantBritishStandardsregardingsafetyandperformancesU.S.A.DENTLABENOREPGSFORPUBLICLISTED(ProductName)(ControlNumber)UNDERWRITERSLABORATORIESMarkElectricalandnon-electricalproductsU.S.A.UNDERWRITERSLABORATORIESMarkElectricalandnon-electricalproductsU.S.A.ULRecognitionElectricalandnon-electricalproductsCENCENMarkMarkissuedbytheEuropeanCommitteeforStandardization(CEN):itguaranteescompliancewiththeEuropeanStandards.CENELECMarkCablesROVEDA N D ARSTPPNDAFETYAN ICERTIFICATIONTRADEMARKDTESTINAORATY13ABB SACE - Electrical devices1.1 General aspects1 Standards12ABB SACE - Electrical devices1.1 General aspects1 Standards

COUNTRYSymbolMarkdesignationApplicability/OrganizationCENELECHarmonizationMarkCertificationmarkprovidingassurancethattheharmonizedcablecomplieswiththerelevantharmonizedCENELECStandardsidentificationthreadECExEUROPEAMarkMarkassuringthecompliancewiththerelevantEuropeanStandardsoftheproductstobeusedinenvironmentswithexplosionhazardsCEEelCEEelMarkMarkwhichisapplicabletosomehouseholdappliances(shavers,electricclocks,etc).15ABB SACE - Electrical devices14ABB SACE - Electrical devices1 Standards

1.2 IEC Standards for electricalinstallationSTANDARDIEC 60027-1

IEC 60034-1

IEC 60617-DB-12M

IEC 61082-1

IEC 61082-2

IEC 61082-3

IEC 61082-4

IEC 60038IEC 60664-1

IEC 60909-0

IEC 60865-1

IEC 60781

IEC 60076-1IEC 60076-2

IEC 60076-3

IEC 60076-5

IEC/TR 60616

IEC 60726IEC 60445YEAR1992

1999

2001

1991

1993

1993

1996

19832000

2001

1993

1989

20001993

2000

2000

1978

19821999TITLELetter symbols to be used in electricaltechnology - Part 1: General

Rotating electrical machines - Part 1:Rating and performanceGraphical symbols for diagrams - 12-month subscription to online databasecomprising parts 2 to 11 of IEC 60617Preparation of documents used inelectrotechnology - Part 1: GeneralrequirementsPreparation of documents used inelectrotechnology - Part 2: Function-oriented diagramsPreparation of documents used inelectrotechnology - Part 3: Connectiondiagrams, tables and listsPreparation of documents used inelectrotechnology - Part 4: Location andinstallation documentsIEC standard voltagesInsulation coordination for equipmentwithin low-voltage systems - Part 1:Principles, requirements and testsShort-circuit currents in three-phase a.c.systems - Part 0: Calculation of currentsShort-circuit currents - Calculation ofeffects - Part 1: Definitions andcalculation methodsApplication guide for calculation of short-circuit currents in low-voltage radialsystemsPower transformers - Part 1: GeneralPower transformers - Part 2: TemperaturerisePower transformers - Part 3: Insulationlevels, dielectric tests and externalclearances in airPower transformers - Part 5: Ability towithstand short circuitTerminal and tapping markings for powertransformersDry-type power transformersBasic and safety principles for man-machine interface, marking andidentification - Identification ofequipment terminals and of terminationsof certain designated conductors,including general rules for analphanumeric system1 Standards

EC - Declaration of ConformityThe EC Declaration of Conformity is the statement of the manufacturer, whodeclares under his own responsibility that all the equipment, procedures orservices refer and comply with specific standards (directives) or other normativedocuments.The EC Declaration of Conformity should contain the following information:name and address of the manufacturer or by its European representative;description of the product;reference to the harmonized standards and directives involved;any reference to the technical specifications of conformity;the two last digits of the year of affixing of the CE marking;identification of the signer.A copy of the EC Declaration of Conformity shall be kept by the manufactureror by his representative together with the technical documentation.1.1 General aspects171.2 IEC standards for electrical installation1 StandardsABB SACE - Electrical devices1.2 IEC standards for electrical installation1 Standards16ABB SACE - Electrical devicesPart 5-6: Control circuit devices andswitching elements DC interface forIEC 60947-6-1

IEC 60947-6-21998

1999proximity sensors and switchingamplifiers (NAMUR)Low-voltage switchgear and controlgear -Part 6-1: Multiple function equipment Automatic transfer switching equipment

Low-voltage switchgear and controlgear -Part 6-2: Multiple function equipment -Control and protective switching devices(or equipment) (CPS)IEC 60947-7-1

IEC 60947-7-2

IEC 60439-1

IEC 60439-2

IEC 60439-3

IEC 60439-41999

1995

1999

2000

2001

1999Low-voltage switchgear and controlgear -Part 7: Ancillary equipment - Section 1:Terminal blocksLow-voltage switchgear and controlgear -Part 7: Ancillary equipment - Section 2:Protective conductor terminal blocks forcopper conductorsLow-voltage switchgear and controlgearassemblies - Part 1: Type-tested andpartially type-tested assembliesLow-voltage switchgear and controlgearassemblies - Part 2: Particularrequirements for busbar trunking systems(busways)Low-voltage switchgear and controlgearassemblies - Part 3: Particularrequirements for low-voltage switchgearand controlgear assemblies intended tobe installed in places where unskilledpersons have access for their use -Distribution boardsLow-voltage switchgear and controlgearassemblies - Part 4: Particularrequirements for assemblies forconstruction sites (ACS)IEC 60439-51999Low-voltage switchgear and controlgearassemblies - Part 5: Particularrequirements for assemblies intended tobe installed outdoors in public places -Cable distribution cabinets (CDCs) forpower distribution in networksIEC 610952000Electromechanical contactors forhousehold and similar purposesSTANDARDIEC 60947-5-6YEAR1999TITLELow-voltage switchgear and controlgear -machine interface, marking andidentification Coding for indicationIEC 60446

IEC 60447

IEC 60947-11999

1993

2001devices and actuatorsBasic and safety principles for man-machine interface, marking andidentification - Identification ofconductors by colours or numeralsMan-machine-interface (MMI) - ActuatingprinciplesLow-voltage switchgear and controlgear -Part 1: General rulesIEC 60947-2

IEC 60947-3

IEC 60947-4-1

IEC 60947-4-2

IEC 60947-4-3

IEC 60947-5-1

IEC 60947-5-22001

2001

2000

2002

1999

2000

1999Low-voltage switchgear and controlgear -Part 2: Circuit-breakersLow-voltage switchgear and controlgear -Part 3: Switches, disconnectors, switch-disconnectors and fuse-combinationunitsLow-voltage switchgear and controlgear -Part 4-1: Contactors and motor-starters Electromechanical contactors and motor-startersLow-voltage switchgear and controlgear -Part 4-2: Contactors and motor-starters AC semiconductor motor controllers andstartersLow-voltage switchgear and controlgear -Part 4-3: Contactors and motor-starters AC semiconductor controllers andcontactors for non-motor loadsLow-voltage switchgear and controlgear -Part 5-1: Control circuit devices andswitching elements - Electromechanicalcontrol circuit devicesLow-voltage switchgear and controlgear -Part 5-2: Control circuit devices andIEC 60947-5-31999switching elements Proximity switchesLow-voltage switchgear and controlgear -Part 5-3: Control circuit devices andIEC 60947-5-41996switching elements Requirements forproximity devices with defined behaviourunder fault conditionsLow-voltage switchgear and controlgear -Part 5: Control circuit devices andswitching elements Section 4: MethodIEC 60947-5-51997of assessing the performance of lowenergy contacts. Special testsLow-voltage switchgear and controlgear -Part 5-5: Control circuit devices andswitching elements - Electricalemergency stop device with mechanicallatching functionSTANDARDIEC 60073YEAR1996TITLEBasic and safety principles for man-191.2 IEC standards for electrical installation1 StandardsABB SACE - Electrical devices1.2 IEC standards for electrical installation1 Standards18ABB SACE - Electrical devices19941994Part 6: Arc welding electrode cablesPart 7: Heat resistant ethylene-vinylacetate rubber insulated cablesIEC 60309-2

IEC 61008-11998

1999

1996Part 8: Cords for applications requiringhigh flexibilityPlugs, socket-outlets and couplers forindustrial purposes - Part 2: Dimensionalinterchangeability requirements for pinand contact-tube accessoriesResidual current operated circuit-breakerswithout integral overcurrent protection forhousehold and similar uses (RCCBs) -Part 1: General rulesIEC 61008-2-1

IEC 61008-2-2

IEC 61009-1

IEC 61009-2-1

IEC 61009-2-21990

1990

1996

1991

1991Residual current operated circuit-breakerswithout integral overcurrent protection forhousehold and similar uses (RCCBs).Part 2-1: Applicability of the general rulesto RCCBs functionally independent ofline voltageResidual current operated circuit-breakerswithout integral overcurrent protection forhousehold and similar uses (RCCBs).Part 2-2: Applicability of the general rulesto RCCBs functionally dependent on linevoltageResidual current operated circuit-breakerswith integral overcurrent protection forhousehold and similar uses (RCBOs) -Part 1: General rulesResidual current operated circuit-breakerswith integral overcurrent protection forhousehold and similar uses (RCBOs)Part 2-1: Applicability of the general rulesto RCBOs functionally independent ofline voltageResidual current operated circuit-breakerswith integral overcurrent protection forhousehold and similar uses (RCBOs) -Part 2-2: Applicability of the general rulesto RCBOs functionallydependent on line voltageIEC 60670

IEC 60669-2-1

IEC 60669-2-2

IEC 606692-31989

2000

2000

1997General requirements for enclosures foraccessories for household and similarfixed electrical installationsSwitches for household and similar fixedelectrical installations - Part 2-1:Particular requirements ElectronicswitchesSwitches for household and similar fixedelectrical installations - Part 2: Particularrequirements Section 2: Remote-controlswitches (RCS)Switches for household and similar fixedelectrical installations - Part 2-3:Particular requirements Time-delayswitches (TDS)STANDARDYEAR1994TITLEPart 5: Lift cablesby extrapolation for partially type-testedassemblies (PTTA) of low-voltageswitchgear and controlgearIEC 61117

IEC 60092-303

IEC 60092-301

IEC 60092-1011992

1980

1980

1994A method for assessing the short-circuitwithstand strength of partially type-testedassemblies (PTTA)Electrical installations in ships. Part 303:Equipment - Transformers for power andlightingElectrical installations in ships. Part 301:Equipment - Generators and motorsElectrical installations in ships - Part 101:Definitions and general requirementsIEC 60092-401

IEC 60092-201

IEC 60092-202

IEC 60092-302

IEC 60092-350

IEC 60092-352

IEC 60364-5-52

IEC 602271980

1994

1994

1997

2001

1997

2001

1998Electrical installations in ships. Part 401:Installation and test of completedinstallationElectrical installations in ships - Part 201:System design - GeneralElectrical installations in ships - Part 202:System design - ProtectionElectrical installations in ships - Part 302:Low-voltage switchgear and controlgearassembliesElectrical installations in ships - Part 350:Shipboard power cables - Generalconstruction and test requirementsElectrical installations in ships - Part 352:Choice and installation of cables for low-voltage power systemsElectrical installations of buildings - Part5-52: Selection and erection of electricalequipment Wiring systemsPolyvinyl chloride insulated cables ofrated voltages up to and including 450/750 VPart 1: General requirements19971997

1997Part 2: Test methodsPart 3: Non-sheathed cables for fixedwiringPart 4: Sheathed cables for fixed wiringIEC 60228IEC 6024519982001

1995

1978

199819981994Part 5: Flexible cables (cords)Part 6: Lift cables and cables for flexibleconnectionsPart 7: Flexible cables screened andunscreened with two or more conductorsConductors of insulated cablesRubber insulated cables - Rated voltagesup to and including 450/750 VPart 1: General requirementsPart 2: Test methodsPart 3: Heat resistant silicone insulatedcablesSTANDARDIEC 60890YEAR1987TITLEA method of temperature-rise assessment211.2 IEC standards for electrical installation1 StandardsABB SACE - Electrical devices1.2 IEC standards for electrical installation1 Standards20STANDARDIEC 61032

IEC 61000-1-1

IEC 61000-1-2

IEC 61000-1-3YEAR1997

1992

2001

2002TITLEProtection of persons and equipment byenclosures - Probes for verificationElectromagnetic compatibility (EMC) -Part 1: General - Section 1: Applicationand interpretation of fundamentaldefinitions and termsElectromagnetic compatibility (EMC) -Part 1-2: General - Methodology for theachievement of the functional safety ofelectrical and electronic equipment withregard to electromagnetic phenomenaElectromagnetic compatibility (EMC) -Part 1-3: General - The effects of high-altitude EMP (HEMP) on civil equipmentand systemsIEC 60269-3-1

IEC 60127-1/10

IEC 60730-2-7

IEC 60364-1

IEC 60364-4

IEC 60364-5

IEC 60364-6

IEC 60364-7

IEC 605292000

1999

198919881996

1988

1994

20011990

2001

2001

20012002

2001

19832002

2001authorized persons (fuses mainly forindustrial application)Low-voltage fuses - Part 3-1:Supplementary requirements for fuses foruse by unskilled persons (fuses mainly forhousehold and similar applications) -Sections I to IVMiniature fuses -Part 1: Definitions for miniature fuses andgeneral requirements for miniature fuse-linksPart 2: Cartridge fuse-linksPart 3: Sub-miniature fuse-linksPart 4: Universal Modular Fuse-Links(UMF)Part 5: Guidelines for quality assessmentof miniature fuse-linksPart 6: Fuse-holders for miniaturecartridge fuse-linksPart 10: User guide for miniature fusesAutomatic electrical controls forhousehold and similar use. Part 2:Particular requirements for timers andtime switchesElectrical installations of buildings - Part 1:Fundamental principles, assessment ofgeneral characteristics, definitionsElectrical installations of buildings - Part 4:Protection for safetyElectrical installations of buildings - Part 5:Selection and erection of electrical equipmentElectrical installations of buildings - Part 6:VerificationElectrical installations of buildings. Part 7:Requirements for special installations orlocationsDegrees of protection provided byenclosures (IP Code)

ABB SACE - Electrical devicesSTANDARDIEC 60079-10

IEC 60079-14

IEC 60079-17

IEC 60269-1

IEC 60269-2YEAR1995

1996

1996

1998

1986TITLEElectrical apparatus for explosive gasatmospheres - Part 10: Classification ofhazardous areasElectrical apparatus for explosive gasatmospheres - Part 14: Electricalinstallations in hazardous areas (otherthan mines)Electrical apparatus for explosive gasatmospheres - Part 17: Inspection andmaintenance of electrical installations inhazardous areas (other than mines)Low-voltage fuses - Part 1: GeneralrequirementsLow-voltage fuses. Part 2: Supplementaryrequirements for fuses for use by2322ABB SACE - Electrical devicesABB SACE - Electrical devices2.1 Introduction2.1 Introduction2 Protection of feeders

Conventional operating current (of a protective device) A specified value ofthe current which cause the protective device to operate within a specifiedtime, designated conventional time.Overcurrent detection A function establishing that the value of current in acircuit exceeds a predetermined value for a specified length of time.Leakage currentElectrical current in an unwanted conductive path other thana short circuit.Fault current The current flowing at a given point of a network resulting froma fault at another point of this network.Wiring systemsWiring system An assembly made up of a cable or cables or busbars and theparts which secure and, if necessary, enclose the cable(s) or busbars.Electrical circuitsElectrical circuit (of an installation) An assembly of electrical equipment oftheinstallationsuppliedfromthesameoriginandprotectedagainstovercurrentsby the same protective device(s).Distribution circuit (of buildings) A circuit supplying a distribution board.Final circuit (of building) A circuit connected directly to current usingequipment or to socket-outlets.

Other equipmentElectrical equipment Any item used for such purposes as generation,conversion, transmission, distribution or utilization of electrical energy, such asmachines,transformers,apparatus,measuringinstruments,protectivedevices,equipment for wiring systems, appliances.Current-using equipment Equipment intended to convert electrical energyinto another form of energy, for example light, heat, and motive powerSwitchgear and controlgear Equipment provided to be connected to anelectrical circuit for the purpose of carrying out one or more of the followingfunctions: protection, control, isolation, switching.Portable equipment Equipment which is moved while in operation or whichcan easily be moved from one place to another while connected to the supply.Hand-held equipment Portable equipment intended to be held in the handduring normal use, in which the motor, if any, forms an integral part of theequipment.Stationary equipment Either fixed equipment or equipment not provided witha carrying handle and having such a mass that it cannot easily be moved.Fixed equipment Equipment fastened to a support or otherwise secured in aspecific location.2 Protection of feeders

The following definitions regarding electrical installations are derived from theStandard IEC 60050.

Characteristics of installationsElectrical installation (of a building) An assembly of associated electricalequipment to fulfil a specific purpose and having coordinated characteristics.Origin of an electrical installation The point at which electrical energy isdelivered to an installation.Neutral conductor (symbol N) A conductor connected to the neutral point ofa system and capable of contributing to the transmission of electrical energy.Protective conductor PE A conductor required by some measures forprotection against electric shock for electrically connecting any of the followingparts:- exposed conductive parts;- extraneous conductive parts;- main earthing terminal;- earth electrode;- earthed point of the source or artificial neutral.

PEN conductor An earthed conductor combining the functions of bothprotective conductor and neutral conductor

Ambient temperature The temperature of the air or other medium where theequipment is to be used.

VoltagesNominal voltage (of an installation) Voltage by which an installation or part ofan installation is designated.Note: the actual voltage may differ from the nominal voltage by a quantity withinpermitted tolerances.

CurrentsDesign current (of a circuit) The current intended to be carried by a circuit innormal service.Current-carrying capacity (of a conductor) The maximum current which canbe carried continuously by a conductor under specified conditions without itssteady-state temperature exceeding a specified value.Overcurrent Any current exceeding the rated value. For conductors, the ratedvalue is the current-carrying capacity.Overload current (of a circuit) An overcurrent occurring in a circuit in theabsence of an electrical fault.Short-circuit current An overcurrent resulting from a fault of negligibleimpedancebetweenliveconductorshavingadifferenceinpotentialundernormaloperating conditions.1SDC010001F09012524Conductors andcablesBare conductorsInsulated conductorsSheathed cables(including armoured andmineral insulated)Multi-core

Single-core--+

0--+

+Without Clippedfixings direct Conduit-++

+Cable trunking(including skirtingtrunking, flush floortrunking)-++

+Cableducting-++

+Cable ladder--+

+++0

0Cable tray On in- SupportCable brackets sulators wire--+

++ Permitted. Not permitted.0 Not applicable, or not normally used in practice.

ABB SACE - Electrical devices- verification of the protection against short-circuit: the specific let-through energybythecircuitbreakerundershort-circuitconditionsshallbelowerthanthespecificlet-through energy which can be withstood by the cable:I2tk2S2- verification of the protection against indirect contacts (depending on thedistribution system).

Verification of the coordination with other equipments (discrimination andback-up, verification of the coordination with switch disconnectors...)negativeoutcomenegativeoutcomeDefinition of the components (auxiliary circuits, terminals) and switchboarddesign

ABB SACE - Electrical devices2 Protection of feeders

2.2 Installation and dimensioning of cables

For a correct dimensioning of a cable, it is necessary to:choose the type of cable and installation according to the environment;choose the cross section according to the load current;verify the voltage drop.

2.2.1 Current carrying capacity and methods of installationSelection of the cableThe international reference Standard ruling the installation and calculation ofthe current carrying capacity of cables in residential and industrial buildings isIEC 60364-5-52 Electrical installations of buildings Part 5-52 Selection andErection of Electrical Equipment- Wiring systems.The following parameters are used to select the cable type:conductive material (copper or aluminium): the choice depends on cost,dimension and weight requirements, resistance to corrosive environments(chemical reagents or oxidizing elements). In general, the carrying capacity ofa copper conductor is about 30% greater than the carrying capacity of analuminium conductor of the same cross section. An aluminium conductor ofthe same cross section has an electrical resistance about 60% higher and aweight half to one third lower than a copper conductor.

insulation material (none, PVC, XLPE-EPR): the insulation material affects themaximumtemperatureundernormalandshort-circuitconditionsandthereforethe exploitation of the conductor cross section [see Chapter 2.4 Protectionagainst short-circuit].

thetypeofconductor(bareconductor,single-corecablewithoutsheath,single-core cable with sheath, multi-core cable) is selected according to mechanicalresistance, degree of insulation and difficulty of installation (bends, joints alongthe route, barriers...) required by the method of installation.

Table 1 shows the types of conductors permitted by the different methods ofinstallation.Table 1: Selection of wiring systemsMethod of installation2.1 Introduction2 Protection of feeders

Installation dimensioningThe flow chart below suggests the procedure to follow for the correctdimensioning of a plant.

Load analysis:-definition of the power absorbed by the loads and relevant position;-definition of the position of the power distribution centers (switchboards);-definition of the paths and calculation of the length of the connection elements;-definition of the total power absorbed, taking into account the utilization factorsand demand factors.

Dimensioning of transformers and generators with margin connected tofuturepredictablepowersupplyrequirements(byapproximationfrom+1530%)

Dimensioning of conductors:- evaluation of the current (Ib) in the single connection elements;- definition of the conductor type (conductors and insulation materials,configuration,...);- definition of the cross section and of the current carrying capacity;- calculation of the voltage drop at the load current under specific referenceconditions (motor starting,).

Verification of the voltage drop limits at the final loadsnegativeoutcomeShort-circuit current calculation maximum values at the busbars (beginning ofline) and minimum values at the end of line

Selection of protective circuit-breakers with:- breaking capacity higher than the maximum prospective short-circuit current;- rated current In not lower than the load curren Ib;- characteristics compatible with the type of protected load (motors, capacitors...).

Verification of the protection of conductors:- verification of the protection against overload: the rated current or the set currentof the circuit-breaker shall be higher than the load current, but lower than thecurrent carrying capacity of the conductor:IbInIz

MethodsofinstallationItemn.DescriptionReferencemethodofinstallationtobeusedtoobtaincurrent-carryingcapacityRoom1Insulatedconductorsorsingle-corecablesinconduitinathermallyinsulatedwallA1Room2Multi-corecablesinconduitinathermallyinsulatedwallA2Room3Multi-corecabledirectinathermallyinsulatedwallA14Insulatedconductorsorsingle-corecablesinconduitonawooden,ormasonrywallorspacedlessthan0.3timesconduitdiameterfromitB15Multi-corecableinconduitonawooden,ormasonrywallorspacedlessthan0.3timesconduitdiameterfromitB267Insulatedconductorsorsingle-corecablesincabletrunkingonawoodenwallrunhorizontally(6)runvertically(7)B189Insulatedconductorsorsingle-corecableinsuspendedcabletrunking(8)Multi-corecableinsuspendedcabletrunking(9)B1(8)orB2(9)12Insulatedconductorsorsingle-corecableruninmouldingsA1TVISDNTVISDN1314Insulatedconductorsorsingle-corecablesinskirtingtrunking(13)Multi-corecableinskirtingtrunking(14)B1(13)orB2(14)15Insulatedconductorsinconduitorsingle-coreormulti-corecableinarchitraveA116Insulatedconductorsinconduitorsingle-coreormulti-corecableinwindowframesA12021Single-coreormulti-corecables:fixedon,orspacedlessthan0.3times(20)cablediameterfromawoodenwallfixeddirectlyunderawoodenceiling(21)C1SDC010001F02012726ABB SACE - Electrical devicesABB SACE - Electrical devicesWithoutfixings40, 46,15, 1656

72, 73

57, 58

-

-With0

56

0

3

20, 21

-fixings Conduit15, 16

54, 55

70, 711, 259, 604, 5

0(including skirtingtrunking, flush floortrunking)-

0

-50, 51, 52,536, 7, 8, 9,12, 13, 1410, 11Cableducting0

44

70, 71

44, 45

6, 7, 8, 9

-Cable ladderCable tray30, 31,32, 33, 3430, 31, 32,33, 340

030, 31,32, 33, 3430, 31, 32,33, 34OnCable brackets insulators-

-

-

-

36

36Supportwire-

-

-

-

-

35The number in each box indicates the item number in Table 3.- Not permitted.0 Not applicable or not normally used in practice.SituationsBuilding voids

Cable channelBuried inGroundEmbedded inStructureSurfaceMountedOverhead2.2 Installation and dimensioning of cables2 Protection of feeders

For industrial installations, multi-core cables are rarely used with cross sectiongreater than 95 mm2.

Methods of installationTo define the current carrying capacity of the conductor and therefore to identifythe correct cross section for the load current, the standardized method ofinstallation that better suits the actual installation situation must be identifiedamong those described in the mentioned reference Standard.FromTables2and3itispossibletoidentifytheinstallationidentificationnumber,the method of installation (A1, A2, B1, B2, C, D, E, F, G) and the tables todefine the theoretical current carrying capacity of the conductor and anycorrection factors required to allow for particular environmental and installationsituations.

Table 2: Method of installationMethod of installationCable trunking2.2 Installation and dimensioning of cables2 Protection of feeders

Table 3: Examples of methods of installation

MethodsofinstallationItemn.DescriptionReferencemethodofinstallationtobeusedtoobtaincurrent-carryingcapacity0.3De0.3De301OnunperforatedtrayC0.3De0.3De311OnperforatedtrayEorF0.3De0.3De321OnbracketsoronawiremeshEorF33Spacedmorethan0.3timescablediameterfromawallEorForG34OnladderEorF35Single-coreormulti-corecablesuspendedfromorincorporatingasupportwireEorF36BareorinsulatedconductorsoninsulatorsGMethodsofinstallationItemn.DescriptionReferencemethodofinstallationtobeusedtoobtaincurrent-carryingcapacityVDe40Single-coreormulti-corecableina2buildingvoid1.5DeV I' bktot=k 1*k 2*k 3S [mm2]Iz = I 0*k tot

ENDThermal resistivity 2.5 Km/W?nok3 = 1k3 fromtable 14k2=k 2'*k 2''k2 fromtable 72 Protection of feeders

START

selection of wiring systems table 1erection of wiringsystems table 2

Method of installation table 3Ib1nk2''=nok2 = 12 Protection of feeders

To summarize:Use this procedure to determine the cross section of the cable:1. from Table 10, determine the correction factor k1 according to the insulationmaterial and the ground temperature;

2. use Table 11, Table 12, Table 13 or the formula for groups of non-similarcables to determine the correction factor k2 according to the distancebetween cables or ducts;

3. fromTable14determinefactork3 correspondingtothesoilthermalresistivity;4. calculate the value of the current Ib by dividing the load current Ib (or therated current of the protective device) by the product of the correction factorscalculated:'k1k2k3 ktot5. fromTable15,determinethecrosssectionofthecablewithI0Ib,accordingto the method of installation, the insulation and conductive material and thenumber of live conductors;6. the actual cable current carrying capacity is calculated by.Table 15: Current carrying capacity of cables buried in the groundI z = I 0k1k2k31SDC010007F00015150ABB SACE - Electrical devicesABB SACE - Electrical devicesCNBAI b ='I bktot'I bktot.0.86I b ='Ib =I N0.86I b = I N'IIII bktotIN =.3.ksignificant effect on the current-carrying capacity of the cables in the circuit.Third harmonic contentof phase current%0 1515 3333 45> 45Size selection isbased on phasecurrent10.86--Current to take inaccount for thecable selectionIb--Size selection isbased on neutralcurrent--0.861Current to take inaccount for thecable selectionIb--2.2 Installation and dimensioning of cables2 Protection of feeders

Equipment likely to cause significant harmonic currents are, for example,fluorescent lighting banks and dc power supplies such as those found incomputers(forfurtherinformationonharmonicdisturbancesseetheIEC61000).The reduction factors given in Table 16 only apply in the balanced three-phasecircuits (the current in the fourth conductor is due to harmonics only) to cableswhere the neutral conductor is within a four-core or five-core cable and is of thesame material and cross-sectional area as the phase conductors. Thesereduction factors have been calculated based on third harmonic currents. Ifsignificant, i.e. more than 10 %, higher harmonics (e.g. 9th, 12th, etc.) areexpected or there is an unbalance between phases of more than 50 %, thenlower reduction factors may be applicable: these factors can be calculated onlyby taking into account the real shape of the current in the loaded phases.Where the neutral current is expected to be higher than the phase current thenthe cable size should be selected on the basis of the neutral current.Where the cable size selection is based on a neutral current which is notsignificantlyhigherthanthephasecurrent,itisnecessarytoreducethetabulatedcurrent carrying capacity for three loaded conductors.If the neutral current is more than 135 % of the phase current and the cable sizeis selected on the basis of the neutral current, then the three phase conductorswillnotbefullyloaded.Thereductioninheatgeneratedbythephaseconductorsoffsets the heat generated by the neutral conductor to the extent that it is notnecessary to apply any reduction factor to the current carrying capacity forthree loaded conductors.

Table 16: Reduction factors for harmonic currents in four-core andfive-core cables

Reduction factorWhere IN is the current flowing in the neutral calculated as follows:Ib is the load current;ktot is the total correction factor;kIII is the third harmonic content of phase current;2.2 Installation and dimensioning of cables2 Protection of feeders

Note on current carrying capacity tables and loaded conductorsTables 8, 9 and 15 provide the current carrying capacity of loaded conductors(current carrying conductors) under normal service conditions.In single-phase circuits, the number of loaded conductors is two.In balanced or slightly unbalanced three-phase circuits the number of loadedconductors is three, since the current in the neutral conductor is negligible.In three-phase systems with high unbalance, where the neutral conductor in amulti-corecablecarriescurrentasaresultofanunbalanceinthephasecurrentsthe temperature rise due to the neutral current is offset by the reduction in theheat generated by one or more of the phase conductors. In this case theconductor size shall be chosen on the basis of the highest phase current. In allcases the neutral conductor shall have an adequate cross section.

Effect of harmonic currents on balanced three-phasesystems: reduction factors for harmonic currents in four-coreandfive-corecableswithfourcorescarryingcurrentWhere the neutral conductor carries current without a corresponding reductionin load of the phase conductors, the current flowing in the neutral conductorshall be taken into account in ascertaining the current-carrying capacity of thecircuit.This neutral current is due to the phase currents having a harmonic contentwhich does not cancel in the neutral. The most significant harmonic whichdoes not cancel in the neutral is usually the third harmonic. The magnitude ofthe neutral current due to the third harmonic may exceed the magnitude of thepower frequency phase current. In such a case the neutral current will have a

1SDC010008F00015352ABB SACE - Electrical devicesABB SACE - Electrical devicesadbck 1 = 0.87I bk1k2'=212.85A1000.87.0.54=I b =2.2 Installation and dimensioning of cables2 Protection of feeders

Procedure:Type of installationIn Table 3, it is possible to find the reference number of the installation and themethod of installation to be used for the calculations. In this example, thereference number is 31, which corresponds to method E (multi-core cable ontray).

Correction factor of temperature k1From Table 4, for a temperature of 40 C and PVC insulation material, k1 =0.87.Correction factor for adjacent cables k2For the multi-core cables grouped on the perforated tray see Table 5.As a first step, the number of circuits or multi-core cables present shall bedetermined; given that:each circuit a), b) and d) constitute a separate circuit;circuit c) consists of three circuits, since it is composed by three cables inparallel per phase;the cable to be dimensioned is a multi-core cable and therefore constitutes asingle circuit;the total number of circuits is 7.Referring to the row for the arrangement (cables bunched) and to the columnfor the number of circuits (7)k 2 = 0.54

After k1 and k2 have been determined, Ib is calculated by:From Table 8, for a multi-core copper cable with PVC insulation, method ofinstallationE,withthreeloadedconductors,acrosssectionwithcurrentcarryingcapacity of I0 Ib = 212.85 A, is obtained. A 95 mm2 cross section cable cancarry, under Standard reference conditions, 238 A.The current carrying capacity, according to the actual conditions of installation,is Iz = 238 . 0.87. 0.54 = 111.81 A2.2 Installation and dimensioning of cables2 Protection of feeders

Example of cable dimensioning in a balanced three-phase circuit without harmonicsDimensioning of a cable with the following characteristics: conductor material: : copper insulation material:

type of cable:

installation::

:

:PVC

multi-core

cables bunched on horizontalperforated tray load current::100 AInstallation conditions: ambient temperature::40 C adjacent circuits witha) three-phase circuit consisting of 4single-core cables, 4x50 mm2;

b) three-phase circuit consisting of onemulti-core cable, 1x(3x50) mm2;

c) three-phase circuit consisting of 9single-core (3 per phase) cables,9x95 mm2;

d) single-phase circuit consisting of 2single-core cables, 2x70 mm2.I b . .3 kIII =115.3.0.6=207A5554ABB SACE - Electrical devicesABB SACE - Electrical devicesI bk1k2'=115AI b =.1150.86'=1337A=I bk1.k2.0.86I b =ktot3 kIII =115.3.0.4=138AI N =1380.86I N0.86'=160.5A=I b =I b . .ktotI N ='I b = I N =207Aand current Ib is:From Table 8, a 95 mm2 cable with current carrying capacity of 238 A must beselected.2.2 Installation and dimensioning of cables2 Protection of feeders

Example of dimensioning a cable in a balanced three-phase circuit with a significant third-harmonic contentDimensioning of a cable with the following characteristics: conductor material: : copper insulation material::PVC type of cable::multi-core installation::layer on horizontal perforated tray:115 A load current:

Installation conditions::30 C ambient temperature:

no adjacent circuits.

Procedure:Type of installationOn Table 3, it is possible to find the reference number of the installation and themethod of installation to be used for the calculations. In this example, thereference number is 31, which corresponds to method E (multi-core cable ontray).Temperature correction factor k1From Table 4, for a temperature of 30 C and PVC insulation materialk 1 = 1

Correction factor for adjacent cables k2As there are no adjacent cables, so

k 2 = 1After k1 and k2 have been determined, Ib is calculated by:2.2 Installation and dimensioning of cables2 Protection of feeders

If no harmonics are present, from Table 8, for a multi-core copper cable withPVC insulation, method of installation E, with three loaded conductors, a crosssection with current carrying capacity of I0 Ib = 115 A, is obtained. A 35 mm2cross section cable can carry, under Standard reference conditions, 126 A.The current carrying capacity, according to the actual conditions of installation,is still 126 A, since the value of factors k1 and k2 is 1.The third harmonic content is assumed to be 28%.Table 16 shows that for a third harmonic content of 28% the cable must bedimensioned for the current that flows through the phase conductors, but areduction factor of 0.86 must be applied. The current Ib becomes:From Table 8, a 50 mm2 cable with carrying capacity of 153 A shall be selected.

If the third harmonic content is 40 %, Table 16 shows that the cable shall bedimensioned according to the current of the neutral conductor and a reductionfactor of 0.86 must be applied.The current in the neutral conductor is:and the value of current Ib is:From Table 8, a 70 mm2 cable with 196 A current carrying capacity shall beselected.If the third harmonic content is 60 %, Table 16 shows that the cable shall bedimensioned according to the current of the neutral conductor, but a reductionfactor of 1 must be applied.The current in the neutral conductor is:

5756ABB SACE - Electrical devicesABB SACE - Electrical devices= 1- cos2 .100UUru%=(2)2.2 Installation and dimensioning of cables2 Protection of feeders

2.2.2 Voltage dropIn an electrical installation it is important to evaluate voltage drops from thepoint of supply to the load.The performanceof a device maybe impaired ifsupplied with avoltage differentfrom its rated voltage. For example: motors:thetorqueisproportionaltothesquareofthesupplyvoltage;therefore,if the voltage drops, the starting torque shall also decrease, making it moredifficult to start up motors; the maximum torque shall also decrease; incandescent lamps: the more the voltage drops the weaker the beambecomes and the light takes on a reddish tone; discharge lamps: in general, they are not very sensitive to small variations involtage, but in certain cases, great variation may cause them to switch off; electronic appliances: they are very sensitive to variations in voltage and thatis why they are fitted with stabilizers; electromechanical devices: the reference Standard states that devices suchas contactors and auxiliary releases have a minimum voltage below whichtheir performances cannot be guaranteed. For a contactor, for example, theholding of the contacts becomes unreliable below 85% of the rated voltage.To limit these problems the Standards set the following limits: IEC 60364-5-52 Electrical installations of buildings. Selection and erectionof electrical equipment - Wiring systems Clause 525 states that in theabsenceofotherconsiderationsitisrecommendedthatinpracticethevoltagedrop between the origin of consumers installation and the equipment shouldnot be greater than 4% of the rated voltage of the installation. Otherconsiderationsincludestart-uptimeformotorsandequipmentwithhighinrushcurrent.Temporaryconditionssuchasvoltagetransientsandvoltagevariationdue to abnormal operation may be disregarded. IEC60204-1SafetyofmachineryElectricalequipmentofmachinesGeneralrequirements Clause 13.5 recommends that: the voltage drop from thepoint of supply to the load shall not exceed 5% of the rated voltage undernormal operating conditions. IEC60364-7-714Electricalinstallationsofbuildings-Requirementsforspecialinstallations or locations - External lighting installations Clause 714.512requires that the voltage drop in normal service shall be compatible with theconditions arising from the starting current of the lamps.2.2 Installation and dimensioning of cables2 Protection of feeders

Voltage drop calculationFor an electrical conductor with impedance Z, the voltage drop is calculated bythe following formula:LU =kZIb =kIb (rcos + xsin ) [V] (1)nwherek is a coefficient equal to:- 2 for single-phase and two-phase systems;- for three-phase systems;Ib [A] is the load current; if no information are available, the cable carryingcapacity Iz shall be considered;L [km] is the length of the conductor;n is the number of conductors in parallel per phase;r [/km] is the resistance of the single cable per kilometre;x [/km] is the reactance of the single cable per kilometre;cos is the power factor of the load: sinNormally, the percentage value in relation to the rated value Ur is calculated by:Resistance and reactance values per unit of length are set out on the followingtable by cross-sectional area and cable formation, for 50 Hz; in case of 60 Hz,the reactance value shall be multiplied by 1.2.5958ABB SACE - Electrical devicesABB SACE - Electrical devices2.2 Installation and dimensioning of cables2 Protection of feeders

Table 1: Resistance and reactance per unit of length of copper cablesSsingle-core cabler[/km] x[/km]two-core/three-core cabler[/km] x[/km][mm2]1.52.54610162535507095120150185240300@ 80 [C]14.8 0.1688.91 0.1565.57 0.1433.71 0.1352.24 0.1191.41 0.1120.889 0.1060.641 0.1010.473 0.1010.328 0.09650.236 0.09750.188 0.09390.153 0.09280.123 0.09080.0943 0.09020.0761 0.0895@ 80 [C]15.1 0.1189.08 0.1095.68 0.1013.78 0.09552.27 0.08611.43 0.08170.907 0.08130.654 0.07830.483 0.07790.334 0.07510.241 0.07620.191 0.0740.157 0.07450.125 0.07420.0966 0.07520.078 0.075Table 2: Resistance and reactance per unit of length of aluminiumcablesS[mm2]1.52.54610162535507095120150185240300single-core cabler[/km] x[/km]@ 80 [C]24.384 0.16814.680 0.1569.177 0.1436.112 0.1353.691 0.1192.323 0.1121.465 0.1061.056 0.1010.779 0.1010.540 0.09650.389 0.09750,310 0.09390.252 0.09280.203 0.09080.155 0.09020.125 0.0895two-core/three-core cabler[/km] x[/km]@ 80 [C]24.878 0.11814.960 0.1099.358 0.1016.228 0.09553.740 0.08612.356 0.08171.494 0.08131.077 0.07830.796 0.07790.550 0.07510.397 0.07620.315 0.0740.259 0.07450.206 0.07420.159 0.07520.129 0.0752.2 Installation and dimensioning of cables2 Protection of feeders

The following tables show the Ux [V/(A.km)] values by cross section andformation of the cable according to the most common cos values.Table 3: Specific voltage drop at cos = 1 for copper cablesS[mm2]1.52.54610162535507095120150185cos = 1single-core cablesingle-phase three-phase29.60 25.6317.82 15.4311.14 9.657.42 6.434.48 3.882.82 2.441.78 1.541.28 1.110.95 0.820.66 0.570.47 0.410.38 0.330.31 0.270.25 0.21two-core cable three-core cablesingle-phase three-phase30.20 26.1518.16 15.7311.36 9.847.56 6.554.54 3.932.86 2.481.81 1.571.31 1.130.97 0.840.67 0.580.48 0.420.38 0.330.31 0.270.25 0.222403000.19 0.160.15 0.130.19 0.170.16 0.14Table 4: Specific voltage drop at cos = 0.9 for copper cablesS[mm2]1.52.54610162535507095120150185240300cos = 0.9single-core cablesingle-phase three-phase26.79 23.2016.17 14.0110.15 8.796.80 5.894.14 3.582.64 2.281.69 1.471.24 1.080.94 0.810.67 0.580.51 0.440.42 0.360.36 0.310.30 0.260.25 0.220.22 0.19two-core cable three-core cablesingle-phase three-phase27.28 23.6316.44 14.2410.31 8.936.89 5.964.16 3.602.65 2.291.70 1.481.25 1.080.94 0.810.67 0.580.50 0.430.41 0.350.35 0.300.29 0.250.24 0.210.21 0.186160ABB SACE - Electrical devicesABB SACE - Electrical devices2.2 Installation and dimensioning of cables2 Protection of feeders

Table 5: Specific voltage drop at cos = 0.85 for copper cablescos = 0.85S[mm2]1.52.54610162535507095120150185240300single-core cablesingle-phase three-phase25.34 21.9415.31 13.269.62 8.336.45 5.593.93 3.412.51 2.181.62 1.411.20 1.040.91 0.790.66 0.570.50 0.440.42 0.360.36 0.310.30 0.260.26 0.220.22 0.19two-core cable three-core cablesingle-phase three-phase25.79 22.3415.55 13.479.76 8.456.53 5.653.95 3.422.52 2.181.63 1.411.19 1.030.90 0.780.65 0.560.49 0.420.40 0.350.35 0.300.29 0.250.24 0.210.21 0.18Table 6: Specific voltage drop at cos = 0.8 for copper cablescos = 0.8S[mm2]1.52.54610162535507095120150185240300single-core cablesingle-phase three-phase23.88 20.6814.44 12.519.08 7.876.10 5.283.73 3.232.39 2.071.55 1.341.15 0.990.88 0.760.64 0.550.49 0.430.41 0.360.36 0.310.31 0.260.26 0.220.23 0.20two-core cable three-core cablesingle-phase three-phase24.30 21.0514.66 12.699.21 7.986.16 5.343.74 3.232.39 2.071.55 1.341.14 0.990.87 0.750.62 0.540.48 0.410.39 0.340.34 0.290.29 0.250.24 0.210.21 0.192.2 Installation and dimensioning of cables2 Protection of feeders

Table 7: Specific voltage drop at cos=0.75 for copper cablescos = 0.75S[mm2]1.52.54610162535507095120150185240300single-core cablesingle-phase three-phase22.42 19.4213.57 11.758.54 7.405.74 4.973.52 3.052.26 1.961.47 1.281.10 0.950.84 0.730.62 0.540.48 0.420.41 0.350.35 0.310.30 0.260.26 0.230.23 0.20two-core cable three-core cablesingle-phase three-phase22.81 19.7513.76 11.928.65 7.495.80 5.023.52 3.052.25 1.951.47 1.271.08 0.940.83 0.720.60 0.520.46 0.400.38 0.330.33 0.290.29 0.250.24 0.210.22 0.19Table 8: Specific voltage drop at cos = 1 for aluminium cablescos = 1S[mm2]1.52.54610162535507095120150185240300single-core cablesingle-phase three-phase48.77 42.2329.36 25.4318.35 15.8912.22 10.597.38 6.394.65 4.022.93 2.542.11 1.831.56 1.351.08 0.940.78 0.670.62 0.540.50 0.440.41 0.350.31 0.270.25 0.22two-core cable three-core cablesingle-phase three-phase49.76 43.0929.92 25.9118.72 16.2112.46 10.797.48 6.484.71 4.082.99 2.592.15 1.871.59 1.381.10 0.950.79 0.690.63 0.550.52 0.450.41 0.360.32 0.280.26 0.226362ABB SACE - Electrical devicesABB SACE - Electrical devices2.2 Installation and dimensioning of cables2 Protection of feeders

Table 9: Specific voltage drop at cos = 0.9 for aluminium cablescos = 0.9S[mm2]1.52.54610162535507095120150185240300single-core cablesingle-phase three-phase44.04 38.1426.56 23.0016.64 14.4111.12 9.636.75 5.844.28 3.712.73 2.361.99 1.721.49 1.291.06 0.920.78 0.680.64 0.550.53 0.460.44 0.380.36 0.310.30 0.26two-core cable three-core cablesingle-phase three-phase44.88 38.8727.02 23.4016.93 14.6611.29 9.786.81 5.894.31 3.732.76 2.392.01 1.741.50 1.301.06 0.910.78 0.680.63 0.550.53 0.460.44 0.380.35 0.300.30 0.26Table 10: Specific voltage drop at cos = 0.85 for aluminium cablesS[mm2]1.52.54610162535507095120150185240300cos = 0.85single-core cablesingle-phase three-phase41.63 36.0525.12 21.7515.75 13.6410.53 9.126.40 5.544.07 3.522.60 2.251.90 1.651.43 1.241.02 0.880.76 0.660.63 0.540.53 0.460.44 0.380.36 0.310.31 0.27two-core cable three-core cablesingle-phase three-phase42.42 36.7325.55 22.1216.02 13.8710.69 9.266.45 5.584.09 3.542.63 2.271.91 1.661.43 1.241.01 0.880.76 0.650.61 0.530.52 0.450,43 0.370.35 0.300.30 0.262.2 Installation and dimensioning of cables2 Protection of feeders

Table 11: Specific voltage drop at cos = 0.8 for aluminium cablescos = 0.8S[mm2]1.52.54610162535507095120150185240300single-core cablesingle-phase three-phase39.22 33.9623.67 20.5014.85 12.869.94 8.616.05 5.243.85 3.342.47 2.141.81 1.571.37 1.180.98 0.850.74 0.640.61 0.530.51 0.450.43 0.380.36 0.310.31 0.27two-core cable three-core cablesingle-phase three-phase39.95 34.5924.07 20.8415.09 13.0710.08 8.736.09 5.273.87 3.352.49 2.161.82 1.571.37 1.180.97 0.840.73 0.630.59 0.510.50 0.440.42 0.360.34 0.300.30 0.26Table 12: Specific voltage drop at cos = 0.75 for aluminium cablesS[mm2]1.52.54610162535507095120150185240300cos = 0.75single-core cablesingle-phase three-phase36.80 31.8722.23 19.2513.95 12.089.35 8.095.69 4.933.63 3.152.34 2.021.72 1.491.30 1.130.94 0.810.71 0.620.59 0.510.50 0.430.42 0.370.35 0.310.31 0.27two-core cable three-core cablesingle-phase three-phase37.47 32.4522.58 19.5614.17 12.279.47 8.205.72 4.963.64 3.152.35 2.031.72 1.491.30 1.120.92 0.800.70 0.600.57 0.490.49 0.420.41 0.350.34 0.290.29 0.25

u%.Ur 2%.400100.I b.L 100.56.0.14=1.02V/(A km)6564ABB SACE - Electrical devicesABB SACE - Electrical devices100=0.51%2.03.400100=U .Uru%=0.052L2=3.42.50.U =U x .I b.=4.28 V100=0.62%4.28.690100=U .Uru%=u%.Ur100.I b .LU xmax =(3)u3=56A350003.400.0.9=P.Ur .cosIb =100=7.05%28.2.400100=U .Uru%==U xmax =.2.2 Installation and dimensioning of cables2 Protection of feeders

Example 1To calculate a voltage drop on a three-phase cable with the followingspecifications: rated voltage: 400 V; cable length: 25 m; cable formation: single-core copper cable, 3x50 mm2; load current Ib: 100 A; power factor cos: 0.9.From Table 4, for a 50 mm2 single-core cable it is possible to read that a Uxvoltage drop corresponds to 0.81 V/(Akm). By multiplying this value by thelength in km and by the current in A, it results:U =U x .I b .L =0.81.100.0.025=2.03 V

which corresponds to this percentage value:Example 2To calculate a voltage drop on a three-phase cable with the followingspecifications: rated voltage: 690 V; cable length: 50 m; cable formation: multi-core copper cable, 2x(3x10) mm2; load current Ib: 50 A; power factor cos: 0.85.From Table 5, for a multi-core 10 mm2 cable it is possible to read that Uxvoltage drop corresponds to 3.42 V/(Akm). By multiplying this value by thelength in km and by the current in A, and by dividing it by the number of cablesin parallel, it results:which corresponds to this percentage value:2.2 Installation and dimensioning of cables2 Protection of feeders

Method for defining the cross section of the conductor according tovoltage drop in the case of long cablesIn the case of long cables, or if particular design specifications impose lowlimits for maximum voltage drops, the verification using as reference the crosssection calculated on the basis of thermal considerations (calculation accordingto chapter 2.2.1 Current carrying capacity and methods of installation) mayhave a negative result.To define the correct cross section, the maximum Uxmax value calculated byusing the formula:is compared with the corresponding values on Tables 412 by choosing thesmallest cross section with a Ux value lower than Uxmax.

Example:Supply of a three-phase load with Pu = 35 kW (Ur=400 V, fr= 50 Hz, cos=0.9)with a 140 m cable installed on a perforated tray, consisting of a multi-corecopper cable with EPR insulation.Maximum permitted voltage drop 2%.Load current Ib is:The Table 8 of Chapter 2.2.1 shows S = 10 mm2.From Table 4, for the multi-core 10 mm2 cable it is possible to read that thevoltage drop per A and per km is 3.60 V/(Akm). By multiplying this value by thelength in km and by the current in A, it results:

U =3.60.Ib.L =3.6.56.0.14=28.2 V

which corresponds to this percentage value:This value is too high.Formula (3) shows:1SDC010009F00013.r .I b 2.L6766ABB SACE - Electrical devicesABB SACE - Electrical devices100=1.6%6.35.400100=U .Uru%=j2jP =[W]2.r .I b .L10001.45IzIzIbInI2I2 1.45.Iz(2)2.2.3 Joule-effect lossesJoule-effect losses are due to the electrical resistance of the cable.The lost energy is dissipated in heat and contributes to the heating of theconductor and of the environment.A first estimate of three-phase losses is:

P = [W]1000whereas single-phase losses are:where:Single-core cableTwo-core/three-core cableS[mm2]1.52.54610162535507095120150185240300Cu14.88.915.573.712.241.410.8890.6410.4730.3280.2360.1880.1530.1230.09430.0761AI24.38414.6809.1776.1123.6912.3231.4651.0560.7790.5400.3890.3100.2520.2030.1550.125Cu15.19.085.683.782.271.430.9070.6540.4830.3340.2410.1910.1570.1250.09660.078AI24.87814.9609.3586.2283.7402.3561.4941.0770.7960.5500.3970.3150.2590.2060.1590.129 Ib is the load current [A]; r is the phase resistance per unit of length of the cable at 80 C [/km] (seeTable 1); L is the cable length [m].

Table 1: Resistance values [/km] of single-core and multi-corecables in copper and aluminium at 80 Cprotected) so that it shall satisfy the two following conditions:

Ib In Iz (1)Where: Ib is the current for which the circuit is dimensioned; Iz is the continuous current carrying capacity of the cable; Inistheratedcurrentoftheprotectivedevice;foradjustableprotectivereleases,the rated current In is the set current; I2 is the current ensuring effective operation in the conventional time of theprotective device.According to condition (1) to correctly choose the protective device, it isnecessary to check that the circuit-breaker has a rated (or set) current that is: higher than the load current, to prevent unwanted tripping; lowerthanthecurrentcarryingcapacityofthecable,topreventcableoverload.The Standard allows an overload current that may be up to 45% greater thanthe current carrying capacity of the cable but only for a limited period(conventional trip time of the protective device).The verification of condition (2) is not necessary in the case of circuit-breakersbecause the protective device is automatically tripped if: I2 = 1.3In for circuit-breakers complying with IEC 60947-2 (circuit-breakersfor industrial use); I2 = 1.45In for circuit-breakers complying with IEC 60898 (circuit-breakersfor household and similar installations).Therefore, for circuit-breakers, if In Iz, the formula I2 1.45Iz will also beverified.When the protective device is a fuse, it is also essential to check formula (2)because IEC 60269-2-1 on Low-voltage fuses states that a 1.6In currentmustautomaticallymeltthefuse.Inthiscase,formula(2)becomes1.6In 1.45Izor In 0.9Iz.2 Protection of feeders

2.3 Protection against overload

The Standard IEC 60364-4-43 Electrical installation of buildings - Protectionagainst overcurrent specifies coordination between conductors and overloadprotective devices (normally placed at the beginning of the conductor to be2.2 Installation and dimensioning of cables2 Protection of feeders

From Table 4 a cross section of 50 mm2 can be chosen.For this cross section Ux = 0.81< 1.02 V/(Akm).By using this value it results:U =U x .I b .L =0.81.56.0.14=6.35 VThis corresponds to a percentage value of:1SDC010010F00011SDC010011F00016968ABB SACE - Electrical devicesABB SACE - Electrical devicesIz

0.9 Iz2.3 Protection against overload2 Protection of feeders

Tosummarize:tocarryoutbyafuseprotectionagainstoverload,thefollowingmust be achieved:Ib In 0.9.Iz

and this means that the cable is not fully exploited.Ib

InCircuit-breaker: choice of rated current

Ib

InFuse: choice of rated currentWhere the use of a single conductor per phase is not feasible, and the currentsin the parallel conductors are unequal, the design current and requirements foroverload protection for each conductor shall be considered individually.

ExamplesExample 1Load specificationsPr = 70 kW; Ur = 400 V; cos = 0.9; three-phase load so Ib = 112 A

Cable specifications

Iz = 134 A

Protective device specificationsT1B160 TMD In125; set current I1 = 125 A2.3 Protection against overload2 Protection of feeders

Example 2Load specificationsPr = 80 kW; cos = 0.9; Ur = 400 V; three-phase load so Ib = 128 A

Cable specificationsIz = 171 A

Protective device specificationsT2N160 PR221DS-LS In160; set current I1 = 0.88 x In = 140.8 A

Example 3Load specificationsPr = 100 kW; cos = 0.9; Ur = 400 V ; three-phase load so Ib = 160 A

Cable specifications

Iz = 190 A

Protective device specificationsT3N250 TMD In200; set current I1 = 0.9 x In = 180 A

Example 4Load specificationsPr = 25 kW; cos = 0.9; Ur = 230 V ; single-phase load so Ib = 121 A

Cable specificationsIz = 134 A

Protective device specificationsT1B160 1P TMF In1251SDC010010F02011SDC010002F09014.76101.322.08105.78107.36102.043.18108.84107.16101.993.11108.65107170ABB SACE - Electrical devicesABB SACE - Electrical devicesPVC300 mm2PVC>300 mm2EPRXLPERubber60 CMineralPVCBareInitial temperature CFinal temperature CMaterial of conductor:CopperAluminiumtin-soldered jointsin copper conductorsaThis value shall be used for bare cables exposed to touch.NOTE 1 Other values of k are under consideration for.- small conductors (particularly for cross section less than 10 mm2);- duration of short-circuit exceeding 5 s;- other types