GUIDELINES FOR ELECTRICAL WIRING IN RESIDENTIAL BUILDINGS

GUIDELINES FORELECTRICAL WIRINGIN RESIDENTIAL BUILDINGS2008 EDITIONwww.st.gov.my

1.2Purpose41.3References5Supply System62.16Electricity Supply SpecificationsElectrical Wiring73.1Legal Requirements73.2Planning of Wiring Work73.3Features of Electrical Wiring103.4Examples of Lighting Circuits Schematic Wiring153.5Examples of Socket Outlets Schematic Wiring173.6Final Circuit For 13A Socket Outlets18Control and Protection System for Electrical Wiring194.1Selection of Control and Protection System forElectrical Wiring194.2Isolation and Switching194.3Protection19Cable Selection225.1Selection of Wiring Cable Type225.2Factors Related To Cable Current Carrying Capacity225.3Use of Minimum Cross Sectional Area Ratings ofWiring Conductors235.4Use of Protection Conductor Minimum Cross23Sectional Area Rating In Comparison with PhaseConductor Cross Sectional Area1

5.5Functions and Colour Identification of Non Flexible23Cables6.7.8.9.5.6Flexible Cables245.7Functions and Colour Identification of FlexibleCables245.8Conductor Insulation and Types of Wiring24Electrical Accessories256.125Selection of Wiring AccessoriesEarthing of Electrical Installations277.1Earthing277.2Classification of Earthing277.3Types and Functions of Earthing Accessories277.4Earthing Arrangements Using a TT System287.5Parts That Are Required To Be Earthed297.6Parts That Are Not Required To Be Earthed297.7Termination To Earth297.8Earth Electrode Resistance30Inspection and Testing of Electrical Wiring318.1Legal Requirements318.2Testing31Appendix ISafety Requirements For Electrical Wiring42Works in Residential BuildingsAppendix IITable of Cable Current Carrying Capacity46Appendix IIITable of Cable Voltage Drops47Appendix IVExample of Cable Voltage Drop (Vd)Calculations48Appendix VForm G (Supervision and CompletionCertificate)492

Appendix VIForm H (Test Certificate)51Appendix VIISymbols53Appendix VIIIAddress of Energy Commission Offices543

CHAPTER 11.1INTRODUCTIONThese Guidelines are based on the Electricity Supply Act 1990, TheElectricity Regulations 1994, MS IEC 60364:2003 Standard: ElectricalInstallations of Buildings, MS 1936:2006 Standard: Electrical Installationsof Buildings – Guide To MS IEC 60364, MS 1979:2007 Standard:Electrical Installation of Buildings – Code of Practice.The Guidelines were formulated through discussions with representativesfrom accredited institutions, technical officers (Safety and Supply) of theEnergy Commission headquarters and comments from the industry.The Energy Commission expresses its gratitude to all those involved, andespecially to MARA (Institut Kemahiran MARA), GIATMARA (PusatGIATMARA), Ministry of Youth and Sports (Institut Kemahiran BeliaNegara and Institut Kemahiran Tinggi Belia Negara), ManpowerDepartment (Institut Latihan Perindustrian) and the industrial sector andinstitutions who have cooperated significantly in the formulation andcompletion of these guidelines.1.2PURPOSEThe Guidelines For Electrical Wiring In Residential Buildings has beenprepared as a wiring guide for all Wiremen and Electrical Contractors forundertaking electrical wiring in residential buildings to conform to theElectricity Regulations 1994.The Guidelines are prepared in a concise and compact manner tofacilitate the electrical wiring of residential buildings to be done adequatelyand to ensure its safety of use while meeting basic wiring requirements.The Guidelines will also be useful for owners of residential buildings orwiring installations to recognise the requirements of safe and adequateelectrical wiring.It is hoped that the Guidelines will ensure that electrical wiring will bebased on correct safety procedures and regulations and to avoid possibleelectrical accidents. Safety requirements in electrical wiring works have tobe met to eliminate accidents causing physical injuries and loss of life orproperty. These requirements are as stated in Appendix 1.4

1.3REFERENCESElectricity Supply Act 1990;Electricity Regulations 1994;MS IEC 60364:2003 Standard: Electrical Installations of Buildings;MS 1936:2006 Standard: Electrical Installations of Buildings – Guide ToMS IEC 60364; andMS 1979:2007 Standard: Electrical Installation of Buildings – Code ofPractice5

CHAPTER 2SUPPLY SYSTEM2.1Electricity Supply SpecificationsElectricity supply for domestic consumers, according to MS IEC 60038standards, meets the following specifications: i.ii.iii.iv.Single phase supply with nominal voltage of 230V, range 10%, -6%;Three phase supply with nominal voltage of 400V, range 10%, -6%;Permitted frequency is 50Hz 1%;Earthing system type (TT System) as in Figure 2.1 and Figure 2.2.All electrical equipment used must be suitable for operation with the statedelectricity supply specifications.6

CHAPTER 3ELECTRICAL WIRING3.1Legal RequirementsRegulation 11(1) of the Electricity Regulations 1994 states that all wiringor rewiring of an installation or extension to an existing installation, whichshall be carried out by an Electrical Contractor or a Private Wiring Unit,have to obtain the approval in writing from a licensee or supply authority.3.2Planning of Electrical Wiring WorkPrior to carrying out wiring work, the wireman/contractor should plan anddetermine the tasks to be undertaken so that the work carried out is tidy,neat and safe to be used. The wireman/contractor shall: i.ii.iii.iv.Undertake a site visit;Determine the consumer load requirements;Calculate the maximum load demand; andSubmit the plans, drawings and specifications.The planning flow chart for building wiring installations is as shown inFigure 3.1.3.2.1 Site VisitThe purpose of the site visit is to determine: i.ii.iii.iv.v.Electrical equipment suitable for use;Maximum load demand;Single or three phase incoming supply;Type of wiring; andEquipment arrangement.3.2.2 Determining Consumer Load RequirementsWith the aid of the building floor plans, the installation requirementssuch as the proposed load, placement of electrical equipment andinstallation design plans can be determined.3.2.2 Calculating Maximum Load DemandThe estimate of the maximum load demand is for determining thespecifications of the wiring equipment such as the cables and7

accessories and subsequently to prepare the electrical installationplans.According to clause 311 of MS IEC 60364 Part 1, to determine themaximum demand for each circuit while ensuring an economic andreliable design within the permitted voltage drop limits. Diversityfactors may be taken into account.The maximum current demand calculations for each circuit must beprepared. These details will show the current requirements, inamperes, for each phase and also assist in determining the cablesizes.Refer to the Third Schedule (Table A and Table B) and Regulation11(2) of the Electricity Regulations 1994 to estimate the maximumcurrent demand and the diversity factors that may be used fordomestic installations.3.2.4 Submission of the Plans, Drawings and SpecificationsRegulation 65 of the Electricity Regulations 1994 states that theeligibility to submit plans is as follows: i.ii.Wireman with Single Phase Restriction – Low voltage singlephase up to 60 amperes.Wireman with Three Phase Restriction – Low voltage up to 60amperes.8

Figure 3.1: The Planning Flow Chart for Single Phase and Three PhaseSupply Building Wiring InstallationsSite VisitPrepare Installation Plansand EquipmentSpecificationsSubmit Form toLicenseeWritten Approvalfrom LicenseeSupervisionby Wireman Maximum LoadType of WiringSingle Phase orThree PhaseDomestic Electricity SupplyApplication Form (Licensee)Prepare Work ScheduleStart Wiring WorkRepairInspection andTestingForms G and H to LicenseePayment of Deposit and Signing ofContractLicensee Installs Meterand Provides ElectricitySupply9

3.3Features of Electrical WiringElectrical wiring composes of electrical equipment such as cables, switchboards, main switches, miniature circuit breakers (MCB) or fuses, residualcurrent devices (RCD), lighting points, power points, lightning arrestors,etc.Example 1 of a single phase consumer electrical wiring is as shown inFigure 3.222X4 MM AK3METERWATER HEATER with Double PoleSwitch110 mA20AK5SUPPLY FROM LICENSEEMAIN SWITCH40A / 60ARCD40A OR 63ADOUBLE POLE(100mA)AIR CONDITIONERDouble Pole SwitchwithLighting/General Power CircuitsCUT OUT UNIT & NEUTRALLINK (LICENSEE)2X1.5MM2 PVC/PVCCIRCUITBREAKER/FUSE20ASPAREK61 NO 13A S/S/O20AK72 NO 13A S/S/O32A4 NO 13A S/S/OK940ADOUBLEPOLE(30mA)K8RCD6 NO 13A S/S/O32A2X2.5MM2 PVC/PVC2X4MM2 PVC/PVCFigure 3.2: Example 1 of a Single Phase Consumer Electrical Wiring10Power Circuits (Socket Outlets)16A

Example 2 of a single phase consumer electrical wiring is as shown inFigure 3.322X4 MM AK3METERWATER HEATER with Double PoleSwitch110 mA20AK5SUPPLY FROM LICENSEEMAIN SWITCH40A / 60ARCD40A OR 63ADOUBLE POLE(100mA)20AAIR CONDITIONERDouble Pole SwitchLighting/General Power CircuitsCUT OUT UNIT & NEUTRALLINK (LICENSEE)2X1.5MM2 PVC/PVCCIRCUITBREAKER/FUSEwithSPAREK61 NO 13A S/S/O20AK72 NO 13A S/S/O32AK84 NO 13A S/S/OK9RCD 40ADOUBLEPOLE(30mA)6 NO 13A S/S/O32A22X2.5MM PVC/PVC2X4MM2 PVC/PVCFigure 3.3: Example 2 of a Single Phase Consumer Electrical Wiring11Power Circuits (Socket Outlets)16A

Example 3 of a single phase consumer electrical wiring is as shown inFigure 3.422X4 MM AK3METERWATER HEATER with Double PoleSwitch110 mA20AK5SUPPLY FROM LICENSEEMAIN SWITCH40A / 60ARCD40A OR 63ADOUBLE POLE(100mA)32AAIR CONDITIONERDouble Pole SwitchwithK6K72 NO 13A S/S/OK84 NO 13A S/S/OK96 NO 13A S/S/O20A32ARCD40ADOUBLEPOLE(30mA)32A2X2.5MM2 PVC/PVC2X4MM2 PVC/PVCFigure 3.4: Example 3 of a Single Phase Consumer Electrical Wiring**Note : The wiring in Figure 3.3 and Figure 3.4 should incorporate a main RCD with atime delay of not exceeding 200ms.12Power Circuits (Socket Outlets)16A1 NO 13A S/S/OLighting/General Power CircuitsCUT OUT UNIT & NEUTRALLINK (LICENSEE)2X1.5MM2 PVC/PVCCIRCUITBREAKER/FUSE

Example 1 of a three phase consumer electrical wiring is as shown in Figure 3.5Lighting/General Power2x1.5MM2 PVC/PVC6A6AR1LIGHT/FANR2LIGHT/FANR3LIGHT/FAN6A6A* BELL/ALARM20ACUT OUT UNIT &NEUTRAL LINKR7AIR CONDITIONER with Double Pole Switch6ASUPPLY FROM LICENSEEMAINSWITCH40A / XHAUST FAN6A6AMSPARE20A10 mAY7WATER HEATER with Double Pole Switch6ALIGHT/FAN216/25MMPVC/PVC dependingon rating of mainswitch. If main switchis 40A then 16 MM2is allowed.6AB2LIGHT/FANB3LIGHT/EXHAUST FAN6A6ASPARE20AB7Note:RCD for three phasesystem should have a residualcurrent device of sensitivity noexceeding 100 mA. If there is nothreephaseloadintheinstallation, it is suggested thatthree units of single phase RCCBsbe installed. This will cause lesssupply interruptions if single phasefaults occur.SPARE with Double Pole Switch2X4 MM2 PVC/PVC32AAMOTOR4X6 MM2 PVC/PVC20ABAIR CONDITIONER with Double Pole Switch20AC2x4MM2MOTOR24X4 MM PVC/PVC16ARCD40ATPN(30mA)20A20A20A20A2x2.5MM2RR2 NO 13A S/S/OR2 NO 13A S/S/OY2 NO 13A S/S/OY2 NO 13A S/S/OY2 NO 13A S/S/O20TPN: Three Pole andNeutral216 MM PVC/PVC20A2020A2032A32A32BB4 NO 13A S/S/OB6 NO 13A S/S/OPower Circuits (Socket Outlets)Figure 3.5: Example 1 of a Three Phase Consumer Electrical Wiring13