GENERAL SPECIFICATIONFORELECTRICAL INSTALLATIONINGOVERNMENT BUILDINGSOFTHE HONG KONG SPECIAL ADMINISTRATIVE REGION2017 EDITIONARCHITECTURAL SERVICES DEPARTMENTTHE GOVERNMENT OF THE HONG KONG SPECIAL ADMINISTRATIVE REGION
PREFACEThis General Specification aims to lay down the technical requirements of materialsand equipment, the standards of workmanship, the requirements on testing andcommissioning, and operation and maintenance as well as requirements on documentsubmissions for Electrical Installation in Government Buildings of the Hong Kong SpecialAdministrative Region (HKSAR).The 2017 edition of this General Specification was developed from the 2012 edition(incorporating Corrigendum No. GSEE02-2012) by the Electrical Specialist Support Groupthat was established under the Building Services Branch Technical Information andResearch & Development Committee of the Architectural Services Department (ArchSD).It incorporates updated international standards and codes as well as technologicaldevelopments which find applications in Hong Kong. To be in line with the Department’sendeavour to reduce the environmental burden on our neighbours and to help preservingcommon resources while improving the quality of our service, this General Specificationputs emphasis on green features and green practices for construction as well as initiatives forenhancement of client satisfaction on completed projects.With the benefit of information technology, electronic version of this edition is to beviewed on and free for download from the ArchSD Internet homepage. As part of theGovernment’s efforts to limit paper consumption, hard copies of this General Specificationwill not be put up for sale.The draft of the 2017 edition has been circulated to stakeholders within and externalto the Government before finalisation. Nevertheless, the ArchSD welcomes comments onits contents at any time since the updating of this General Specification is a continuousprocess for the inclusion of any developments that can help meeting the needs of ourcommunity.
DISCLAIMERThis General Specification is solely compiled for Electrical Installation carried outfor or on behalf of the ArchSD in Government buildings of the HKSAR.There are no representations, either expressed or implied, as to the suitability of thisGeneral Specification for purposes other than that stated above. Users who choose to adoptthis General Specification for their works are responsible for making their own assessmentsand judgement of all information contained here. The ArchSD does not accept any liabilityand responsibility for any special, indirect or consequential loss or damages whatsoeverarising out of or in connection with the use of this General Specification or reliance placedon it.The materials contained in this document may not be pertinent or fully cover theextent of the installation in non-government buildings and there is no intimated or impliedendorsement of the sales, supply and installation of the materials and equipment specified inthis General Specification within the territory of the HKSAR.
TABLE OF CONTENTSPART ASCOPE AND GENERAL REQUIREMENTSSECTION A1SCOPE OF SPECIFICATIONA1.1Installations to Comply with this General SpecificationA1.2Scope of the InstallationsA1.3Terms and DefinitionsA1.4Singular and PluralSECTION A2STATUTORY OBLIGATIONS AND OTHER REGULATIONSA2.1Statutory Obligations and Other RequirementsA2.1.1Statutory ObligationsA2.1.2Other RequirementsA2.1.3Safety RequirementsA2.1.4Technical StandardsA2.2Case of ConflictSECTION A3EXECUTION OF INSTALLATIONSA3.1The International System of Units (SI)A3.2Programme of InstallationsA3.3Builder’s WorkA3.4Coordination of InstallationsA3.5Cooperation with Other ContractorsA3.6Site SupervisionA3.7Sample BoardA3.8Advice of Order PlacedA3.9Record of Materials DeliveryA3.10Protection of Materials and EquipmentA3.11PaintingSECTION A4DRAWINGS AND MANUALSA4.1Drawings in Electronic FormatA4.2Installation DrawingsA4.2.1Drawing Submission ScheduleA4.2.2Size of Installation DrawingsA4.2.3Contents of Installation DrawingsA4.2.4Builder’s Work DrawingsA4.2.5Manufacturer’s Shop DrawingsTable of ContentsPage 1 of 29EE GS2017 Edition
A4.3A4.4A4.2.6Checking Drawings of Other TradesAs-built DrawingsA4.3.1Submission of As-built DrawingsA4.3.2Size of As-built DrawingsA4.3.3Content of As-built DrawingsA4.3.4Framed DrawingsOperation and Maintenance (O&M) Manual and User g and ApprovalA4.4.4Structure and Contents of O&M ManualA4.4.5Structure and Contents of User ManualA4.4.6Intellectual Property RightsTable of ContentsPage 2 of 29EE GS2017 Edition
PART BINSTALLATION METHODOLOGYSECTION B1GENERALB1.1WorkmanshipB1.1.1TradesmenB1.1.2Tool and InstrumentB1.1.3Safety on SiteB1.2Label and NoticeB1.2.1Inscription of Label and EngravingB1.2.2Material for LabelB1.2.3Fixing of LabelB1.2.4Engraving for Electrical AccessoryB1.2.5Warning NoticeB1.2.6Other Labels and NoticesB1.3Guard and Railing for Moving or Rotating Parts of EquipmentB1.4Identification of Cable and ConduitB1.5Fixing to Wooden PlugB1.6Painting of Metal WorkB1.7Water ProofingB1.8Provision of Spare Fuses in Main Switch RoomSECTION B2INSTALLATION OF WIRING SYSTEMSB2.1Wiring in Steel Conduit SystemB2.1.1Type of CableB2.1.2Concealed Steel Conduit SystemB2.1.3Surface Conduit SystemB2.1.4Minimum Size of ConduitB2.1.5Flexible ConduitB2.1.6Conduit ContinuityB2.1.7Joint in ConduitsB2.1.8Provision of Adaptable BoxB2.1.9Spacing between ConduitsB2.1.10 Termination of Conduits at Metal Casing ofEquipmentB2.1.11 Conduit BendB2.1.12 Conduit Crossing Expansion JointB2.1.13 Use of Extension PieceB2.1.14 Prevention of Ingress of Foreign MattersB2.1.15 Prevention of Accumulation of Water or MoistureTable of ContentsPage 3 of 29EE GS2017 Edition
2.1.23B2.2B2.3Conduit Laid Direct in GroundFixing of Distance (Spacing) SaddleConduit Installed Outdoors or in Damp SituationSwabbing Out of ConduitFire BarrierCable Capacity of ConduitMethod of Drawing Cables into ConduitSegregation of Cables of Different CircuitCategoriesB2.1.24 “Looping-in” Wiring SystemB2.1.25 Grouping of Cables in ConduitB2.1.26 Termination of Bonding Conductors at ConduitInstallationWiring in Steel Trunking SystemB2.2.1GeneralB2.2.2Provision of Cable Retaining Bar and CableSupportB2.2.3Cable Capacity of TrunkingB2.2.4Correction Factor of GroupingB2.2.5Segregation of Cables of Different CircuitCategoriesB2.2.6Connection to EquipmentB2.2.7Connection to Distribution BoardB2.2.8Fixing of Surface TrunkingB2.2.9Cables through TrunkingB2.2.10 Fire BarrierB2.2.11 Prevention of Electrolytic ActionB2.2.12 Prevention of Ingress of WaterWiring in Plastic Conduit or Plastic Trunking SystemB2.3.1GeneralB2.3.2Pliable ConduitB2.3.3Joint in PVC ConduitB2.3.4Plastic BoxesB2.3.5Termination of PVC Conduit at Casing ofEquipmentB2.3.6Conduit BendB2.3.7Allowance for Thermal ExpansionB2.3.8Fixing of TrunkingB2.3.9Circuit Protective ConductorB2.3.10 Embedment of Concealed PVC ConduitsTable of ContentsPage 4 of 29EE GS2017 Edition
B2.4B2.5SECTION B3Surface Wiring SystemB2.4.1Type of CableB2.4.2Minimum Size of Live Conductors and CPCB2.4.3Identification of Cable CoreB2.4.4Joint in Cable or CordB2.4.5Installation of Non-flexible CableB2.4.6Installation of Flexible Cable and Flexible CordTool and WorkmanshipB2.5.1Approved ToolB2.5.2Cutting in Metal Work for Conduit or in TrunkingB2.5.3Making Good of Damaged CoatingINSTALLATION OF POWER CABLES, CABLE TRAYS ANDCABLE LADDERSB3.1GeneralB3.1.1ScopeB3.1.2Electromagnetic InterferenceB3.2Cable Mounted on SurfaceB3.3Cable Laid in Enclosed TrenchB3.4Cable Enclosed in DuctB3.4.1GeneralB3.4.2Drawing-in of CablesB3.4.3Internal BarrierB3.4.4Fire BarrierB3.4.5Draw-in PitB3.4.6Segregation of Cables of Different CircuitCategoriesB3.4.7Sealing of Duct Entry to BuildingB3.5Cable Buried Direct in GroundB3.5.1Protection of CableB3.5.2Cable MarkerB3.6Bending Radius of CableB3.7Cable Joint and Cable TerminationB3.7.1GeneralB3.7.2Joint Box and Terminating BoxB3.7.3Identification at Joint or TerminationB3.7.4Earth Continuity across JointB3.7.5Straight-through Joint for Copper ConductorsB3.7.6Tee-joint for Copper ConductorB3.7.7Joint for Aluminium CablesTable of ContentsPage 5 of 29EE GS2017 Edition
B3.7.8B3.8B3.9B3.10B3.11Termination of PVC-insulated or XLPE-insulatedCable with Copper ConductorsB3.7.9Termination of PVC-insulated or XLPE-insulatedCable with Aluminium ConductorsB3.7.10 Use of Heat Shrinkable TubingB3.7.11 Other Methods of Joint and TerminationSpecial Requirements for Mineral Insulated CablesB3.8.1Cable RouteB3.8.2Cable SupportB3.8.3Bending RadiusB3.8.4Cable Loop for Prevention of Vibration and LowTemperature Cold StoreB3.8.5Cable TerminationB3.8.6Insulation ResistanceB3.8.7Bonding of Cable Sheath to MetalworkB3.8.8Laying of Single-core CablesB3.8.9Protection from Mechanical DamageInstallation of Perforated Cable TraysB3.9.1Connection between Adjacent Lengths of TrayB3.9.2Cutting of TrayB3.9.3Hole in TrayB3.9.4Fixing of TrayB3.9.5Fixing of Cable on TrayInstallation of Wire Mesh Cable TraysB3.10.1 GeneralB3.10.2 SupportsB3.10.3 BendsB3.10.4 EarthingB3.10.5 Safety Working LoadInstallation of Cable LadderB3.11.1 Dropout Plate for Cable ExitB3.11.2 Flexible (Expansion) Couplers across BuildingExpansion JointB3.11.3 Ladder CoversB3.11.4 End ConnectorsB3.11.5 EarthingB3.11.6 Minimum Inside Radius of All BendsB3.11.7 SupportsB3.11.8 Safety Working LoadTable of ContentsPage 6 of 29EE GS2017 Edition
SECTION B4INSTALLATION OF GENERAL LIGHTING AND POWERB4.1Installation of Lighting System and LuminairesB4.1.1PendantB4.1.2Luminaire Mounted on PattressB4.1.3Ceiling RoseB4.1.4PaintingB4.1.5Special Requirements for Outdoor LuminairesB4.2Installation of Wiring AccessoriesB4.3Installation of Domestic SwitchesB4.3.1GeneralB4.3.2Lighting SwitchB4.3.3Time SwitchB4.3.4Application in BathroomB4.4Installation of Socket OutletsB4.4.1GeneralB4.4.2Shaver Supply UnitB4.4.3Socket Outlet at Hazardous AreaB4.4.4Socket Outlet of Surface Conduit SystemB4.4.5Socket Outlet for Different Voltage SystemB4.4.6Application in BathroomB4.5Installation of Measuring InstrumentB4.5.1Mounting of Current Transformers AssociatedB4.5.2B4.5.3SECTION B5with Watt-hour MeterIdentification of InstrumentMounting Position of Selector SwitchINSTALLATION OF DOMESTIC APPLIANCESB5.1GeneralB5.1.1Connection to AppliancesB5.1.2(NOT USED)B5.1.3Engraving for IdentificationB5.1.4Earthing of ApplianceB5.1.5Appliance Requiring Exclusive CircuitB5.2Ceiling Fan and Ceiling-mounted Rotary FanB5.2.1Method of SupplyB5.2.2Fixing of FanB5.2.3Fan RegulatorB5.3Wall-mounted FanB5.4Exhaust FanB5.4.1Fixing of FanTable of ContentsPage 7 of 29EE GS2017 Edition
B5.5B5.6B5.7B5.8B5.9B5.10B5.11SECTION B6B5.4.2Method of SupplyElectric Fire or HeaterB5.5.1Wall-mounted RadiatorB5.5.2Panel FireB5.5.3Tubular HeaterWater Heater and Water BoilerB5.6.1Oversink Water HeaterB5.6.2Other Type of Water HeaterB5.6.3Water BoilerTea UrnHousehold Electric CookerHand/Face DryerRoom CoolerB5.10.1 Method of SupplyB5.10.2 Position of Connection UnitRefrigeratorINSTALLATION OF BUSBAR TRUNKING SYSTEMB6.1GeneralB6.2Site Storage and ProtectionB6.3Busbar IdentificationB6.4Joint in BusbarB6.5Expansion UnitB6.6Feeder UnitB6.7Tap-off Unit ConnectionB6.8Fire BarrierB6.9Busbar Trunking AccessoriesB6.10Support of Busbar Trunking SystemB6.11EarthingB6.12Requirements for Air-insulated Busbar Trunking SystemB6.12.1 ApplicationB6.12.2 Busbar SupportsB6.12.3 Tap-offB6.12.4 Fire BarrierB6.12.5 Mounting BracketsB6.13Requirement for All Insulated Busbar Trunking SystemB6.13.1 ApplicationB6.13.2 Busbar JointingB6.13.3 Expansion UnitB6.13.4 Tap-off UnitTable of ContentsPage 8 of 29EE GS2017 Edition
B6.13.5SECTION B7Supporting Hangers and Fixing BracketsINSTALLATION OF EARTHING SYSTEMB7.1GeneralB7.2Main Earthing TerminalB7.3Earth ElectrodeB7.3.1Types of Earth ElectrodeB7.3.2Rod ElectrodeB7.3.3Tape ElectrodeB7.3.4Plate ElectrodeB7.3.5Electrode in Deep Bored HoleB7.3.6Connection between ElectrodesB7.4Earthing ConductorB7.4.1Conductor MaterialB7.4.2Connection to ElectrodesB7.5Main Equipotential Bonding ConductorB7.5.1Conductor MaterialB7.5.2Bonding PositionB7.5.3Bonding MethodB7.6Supplementary Bonding ConductorB7.6.1Conductor MaterialB7.6.2Application in BathroomB7.6.3Application in Other AreasB7.6.4Bonding MethodB7.7Circuit Protective Conductor (CPC)B7.7.1GeneralB7.7.2CPC for Socket OutletB7.7.3CPC for Flexible ConduitB7.7.4CPC for Busbar TrunkingB7.7.5CPC for Ring Final CircuitB7.8Joints in Protective ConductorsB7.9Identification and LabellingB7.9.1Colour IdentificationB7.9.2Label for Earthing and Bonding ConnectionsB7.10Sizing of Protective ConductorB7.10.1 GeneralB7.10.2 Equipotential Bonding ConductorB7.11Earth Fault Loop ImpedanceB7.11.1 Automatic Disconnection TimeB7.11.2 Maximum Earth Loop ImpedanceTable of ContentsPage 9 of 29EE GS2017 Edition
B7.12SECTION B8B7.11.3 Condition for ComplianceUse of Residual Current-operated Circuit BreakerB7.12.1 GeneralB7.12.2 Application in Household InstallationB7.12.3 Equipment Outside an Equipotential ZoneB7.12.4 Circuits in BathroomMISCELLANEOUS INSTALLATIONSB8.1Telecommunication SystemsB8.1.1ScopeB8.1.2Conduit for Telephone, Computer Network,Inter-communication and PA SystemsB8.1.3Outlet Box for Telephone PointB8.1.4Outlet Box for Computer PointB8.1.5Outlet Box for Inter-communication and PASystemB8.1.6Conduit for Staff Paging SystemB8.1.7Conduit for Broadcast Reception SystemB8.1.8Outlet Box for Broadcast Reception SystemB8.2Bell and Audible Warning SystemB8.2.1Class-change Bell System for SchoolsB8.2.2Bell for Mains VoltageB8.2.3Call Bell and Door Bell SystemsB8.2.4Bell and Buzzer for Extra Low VoltageB8.2.5Bell TransformerB8.2.6Call Bell PushB8.2.7Mounting of Call Bell PushB8.2.8Table-type PushB8.2.9Table-type Push in Concealed Conduit InstallationB8.2.10 Bell IndicatorB8.2.11 Segregatio