GENERAL SPECIFICATION FOR ELECTRICAL …

1 GENERAL SPECIFICATION FOR ELECTRICAL installation IN government BUILDINGS OF THE hong kong SPECIAL ADMINISTRATIVE REGION 2012 EDITION ARCHITECTURAL SERVICES DEPARTMENT THE government OF THE hong kong SPECIAL ADMINISTRATIVE REGION PREFACE This GENERAL SPECIFICATION aims to lay down the technical requirements of materials and equipment, the standards of workmanship, the requirements on testing and commissioning as well as requirements on document submissions for ELECTRICAL installation in government Buildings of the hong kong Special Administrative Region (HKSAR). The 2012 edition of this GENERAL SPECIFICATION was developed based on its 2007 edition by the ELECTRICAL Specialist Support Group that was established under the building Services Branch Technical Information and Research & Development Committee of the Architectural Services Department (ArchSD). This new edition comprises revisions in the corrigendum that had been issued for the 2007 edition and, in addition, incorporates updated international standards as well as technological developments which find applications in hong kong .

2 To be in line with the department s endeavour to reduce the environmental burden on our neighbours and to help preserving common resources while improving the quality of our service, this new edition has continued putting emphasis on green initiatives and initiatives for enhancement of client satisfaction on completed projects. With the benefit of information technology, electronic version of this new edition is to be viewed on and free for download from the Architectural Services Department (ArchSD) Internet homepage. As part of the government s efforts to limit paper consumption, hard copies of this GENERAL SPECIFICATION will not be put up for sale. The draft of this edition has been circulated to stakeholders within and external to the government before finalization. Nevertheless, the Architectural Services Department welcomes comments on its contents at anytime since the updating of this GENERAL SPECIFICATION is a continuous process for the inclusion of any developments that can help meeting the needs of our community.

3 DISCLAIMER This GENERAL SPECIFICATION is solely compiled for an ELECTRICAL installation carried out for 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 this GENERAL SPECIFICATION for purposes other than that stated above. Users who choose to adopt this GENERAL SPECIFICATION for their works are responsible for making their own assessments and judgement of all information contained here. The ArchSD does not accept any liability and responsibility for any special, indirect or consequential loss or damage whatsoever arising out of or in connection with the use of this GENERAL SPECIFICATION or reliance placed on it. The materials contained in this document may not be pertinent or fully cover the extent of the installation in non- government buildings and there is no intimated or implied endorsement of the sales, supply and installation of the materials and equipment specified in this GENERAL SPECIFICATION within the territory of the HKSAR.

4 Table of Contents Page 1 of 24 EE_GS 2012 Edition TABLE OF CONTENTS PART A SCOPE AND GENERAL REQUIREMENTS SECTION A1 SCOPE OF SPECIFICATION Installations to Comply with this GENERAL SPECIFICATION Scope of the Installations Terms and Definitions Singular and Plural SECTION A2 STATUTORY OBLIGATIONS AND OTHER REGULATIONS Statutory Obligations and Other Requirements Statutory Obligations Other Requirements Safety Requirements Technical Standards Case of Conflict SECTION A3 EXECUTION OF INSTALLATIONS The International System of Units (SI) Programme of Installations Builder s Work Coordination of Installations Cooperation with Other Contractors Site Supervision Sample Board Advice of Order Placed Record of Materials Delivery Protection of Materials and Equipment SECTION A4 DRAWINGS AND MANUALS Drawings in Electronic Format installation Drawings Drawing Submission Schedule Size of installation Drawings Contents of installation Drawings Builder s Work Drawings Manufacturer s Shop Drawings Table of Contents Page 2 of 24 EE_GS 2012 Edition As-built Drawings Submission of As-built Drawings Size of As-built Drawings Content of As-built Drawings Framed Drawings Operation and Maintenance (O&M)

5 Manual and User Manual GENERAL Presentation Checking and Approval Structure and Contents of O&M Manual Structure and Contents of User Manual Intellectual Property Rights Table of Contents Page 3 of 24 EE_GS 2012 Edition PART B installation METHODOLOGY SECTION B1 GENERAL Workmanship Tradesmen Tool and Instrument Safety on Site Label and Notice Inscription of Label and Engraving Material for Label Fixing of Label Engraving for ELECTRICAL Accessory Warning Notice Other Labels and Notices Guard and Railing for Moving or Rotating Parts of Equipment Identification of Cable and Conduit Fixing to Wooden Plug Painting of Metal Work Water Proofing Provision of Spare Fuses in Main Switch Room SECTION B2 installation OF WIRING SYSTEMS Wiring in Steel Conduit System Type of Cable Concealed Steel Conduit System Surface Conduit System Minimum Size of Conduit Flexible Conduit Conduit Continuity Joint in Conduits Provision of Adaptable Box Spacing between Conduits Termination of Conduits at Metal Casing of Equipment Conduit Bend Conduit Crossing Expansion Joint Use of Extension Piece Prevention of Ingress of Foreign Matters Prevention of Accumulation of Water or Moisture Conduit Laid Direct in Ground Fixing of Distance (Spacing)

6 Saddle Conduit Installed Outdoors or in Damp Situation Swabbing Out of Conduit Fire Barrier Cable Capacity of Conduit Method of Drawing Cables into Conduit Segregation of Cables of Different Circuit Categories Table of Contents Page 4 of 24 EE_GS 2012 Edition Looping-in Wiring System Grouping of Cables in Conduit Termination of Bonding Conductors at Conduit installation Wiring in Steel Trunking System GENERAL Provision of Cable Retaining Bar and Cable Support Cable Capacity of Trunking Correction Factor of Grouping Segregation of Cables of Different Circuit Categories Connection to Equipment Connection to Distribution Board Fixing of Surface Trunking Cables through Trunking Fire Barrier Prevention of Electrolytic Action Prevention of Ingress of Water Wiring in Plastic Conduit or Plastic Trunking System GENERAL Pliable Conduit Joint in PVC Conduit Plastic Boxes Termination of PVC Conduit at Casing of Equipment Conduit Bend Allowance for Thermal Expansion Fixing of Trunking Earthing Surface Wiring System Type of Cable Minimum Size of Live Conductors and CPC Identification of Cable Core Joint in Cable or Cord installation of Non-flexible Cable installation of Flexible Cable and Flexible Cord Tool and Workmanship Approved Tool Cutting in Metal Work for Conduit or in Trunking Making Good of Damaged Coating Table of Contents Page 5 of 24 EE_GS 2012 Edition SECTION B3 installation OF POWER CABLES.

7 CABLE TRAYS AND CABLE LADDERS GENERAL Scope Electromagnetic Interference Cable Mounted on Surface Cable Laid in Enclosed Trench Cable Enclosed in Duct GENERAL Drawing-in of Cables Internal Barrier Fire Barrier Draw-in Pit Segregation of Cables of Different Circuit Categories Sealing of Duct Entry to building Cable Buried Direct in Ground Protection of Cable Cable Marker Bending Radius of Cable Cable Joint and Cable Termination GENERAL Joint Box and Terminating Box Identification at Joint or Termination Earth Continuity across Joint Straight-through Joint for Copper Conductors Tee-joint for Copper Conductor Joint for Aluminium Cables Termination of PVC-insulated or XLPE-insulated Cable with Copper Conductors Termination of PVC-insulated or XLPE-insulated Cable with Aluminium Conductors Use of Heat Shrinkable Tubing Other Methods of Joint and Termination Special Requirements for Mineral Insulated Cables Cable Route Cable Support Bending Radius Cable Loop for Prevention of Vibration and Low Temperature Cold Store Cable Termination Insulation Resistance Bonding of Cable Sheath to Metalwork Laying of Single-core Cables Protection from Mechanical Damage installation of Perforated Cable Trays Connection between Adjacent Lengths of Tray Cutting of Tray Hole in Tray Fixing of Tray Fixing of Cable on Tray Table of Contents Page 6 of 24 EE_GS 2012 Edition installation of Wire Mesh Cable Trays GENERAL Supports Bends Earthing Safety Working Load installation of Cable Ladder Dropout Plate for Cable Exit Flexible (Expansion)

8 Couplers across building Expansion Joint Ladder Covers End Connectors Earthing Minimum Inside Radius of All Bends Supports Working Load SECTION B4 installation OF GENERAL LIGHTING AND POWER installation of Lighting System and Luminaires Pendant Luminaire Mounted on Pattress Ceiling Rose Painting Special Requirements for Outdoor Luminaires installation of Wiring Accessories installation of Domestic Switches GENERAL Lighting Switch Time Switch Application in Bathroom installation of Socket Outlets GENERAL Shaver Supply Unit Socket Outlet at Hazardous Area Socket Outlet of Surface Conduit System Socket Outlet for Different Voltage System Application in Bathroom installation of Measuring Instrument Mounting of Current Transformers Associated with Watt-hour Meter Identification of Instrument Mounting Position of Selector Switch SECTION B5 installation OF DOMESTIC APPLIANCES GENERAL Connection to Appliances (NOT USED)

9 Engraving for Identification Earthing of Appliance Table of Contents Page 7 of 24 EE_GS 2012 Edition Appliance Requiring Exclusive Circuit Ceiling Fan and Ceiling-mounted Rotary Fan Method of Supply Fixing of Fan Fan Regulator Wall-mounted Fan Exhaust Fan Fixing of Fan Method of Supply Electric Fire or Heater Wall-mounted Radiator Panel Fire Tubular Heater Water Heater and Water Boiler Oversink Water Heater Other Type of Water Heater Water Boiler Tea Urn Household Electric Cooker Hand/Face Dryer Room Cooler Method of Supply Position of Connection Unit Refrigerator SECTION B6 installation OF BUSBAR TRUNKING SYSTEM GENERAL Site Storage and Protection Busbar Identification Joint in Busbar Expansion Unit Feeder Unit Tap-off Unit Connection Fire Barrier Busbar Trunking Accessories Support of Busbar Trunking System Earthing Requirements for Air-insulated Busbar Trunking System Application Busbar Supports Tap-off Fire Barrier Mounting Brackets Requirement for All Insulated Busbar Trunking System Application Busbar Jointing Expansion Unit Tap-off Unit Supporting Hangers and Fixing Brackets Table of Contents Page 8 of 24 EE_GS 2012 Edition SECTION B7 installation OF EARTHING SYSTEM GENERAL Main Earthing Terminal Earth Electrode Types of Earth Electrode Rod Electrode Tape Electrode Plate Electrode Electrode in Deep Bored Hole Connection between Electrodes Earthing Conductor Conductor Material Connection to Electrodes Main Equipotential Bonding Conductor Conductor Material Bonding Position Bonding Method Supplementary Bonding Conductor Conductor Material Application in Bathroom Application in Other Areas Bonding Method Circuit Protective Conductor (CPC)

10 GENERAL CPC for Socket Outlet CPC for Flexible Conduit CPC for Busbar Trunking CPC for Ring Final Circuit Joints in Protective Conductors Identification and Labelling Colour Identification Label for Earthing and Bonding Connections Sizing of Protective Conductor GENERAL Equipotential Bonding Conductor Earth Fault Loop Impedance Automatic Disconnection Time Maximum Earth Loop Impedance Condition for Compliance Use of Residual Current-operated Circuit Breaker GENERAL Application in Household installation Equipment Outside an Equipotential Zone Circuits in Bathroom Table of Contents Page 9 of 24 EE_GS 2012 Edition SECTION B8 MISCELLANEOUS INSTALLATIONS Telecommunication Systems Scope Conduit for Telephone, Computer Network, Inter-communication and PA Systems Outlet Box for Telephone Point Outlet Box for Computer Point Outlet Box for Inter-communication and PA System Conduit for Staff Paging System Conduit for Broadcast Reception System Outlet Box for Broadcast Reception System Bell and Audible Warning System Class-change Bell System for Schools Bell for Mains Voltage Call Bell and Door Bell Systems Bell and Buzzer for Extra Low Voltage Bell Transformer Call Bell Push Mounting of Call Bell Push Table-type Push Table-type Push in Concealed Conduit installation Bell Indicator Segregation of Circuits installation in Hazardous Areas GENERAL ELECTRICAL Equipment Selection Wiring System Conduit Fitting, Cable Glands, Terminal Box and Enclosure Screw or Bolt Luminaire Conduit Pendant Cables or Conduits Passing through Floor.