Code of Practice for the Electricity Code of Practice Code of Practice for the Electricity (Wiring) Regulations 2015 Edition ( Wiring ) Regulations $71 2015 Edition Electricity Legislation 3 Kai Shing Street, Kowloon, Hong Kong Tel: (852) 1823 Fax: (852) 2895 4929 Website: www.emsd.gov.hk Email: [email protected] Cover Designed by the Information Services Department Printed by the Government Logistics Department Hong Kong Special Administrative Region Government CODE OF PRACTICE FOR THE ELECTRICITY (WIRING) REGULATIONS Electrical and Mechanical Services Department 2015 Contents Page Acknowledgements 9 Part I 1. Introduction 10 2. Interpretation 11 3. Application 16 3A General Application of the CoP 17 3B Application to Category 2 Circuit 17 3C Exempted Fixed Electrical Installations 17 4. General Safety Requirements 18 4A General 19 4B Workmanship and Materials 20 4C Design, Construction, Installation and Protection 20 4D Identification, Maintenance, Inspection and Testing 21 4E Working Space 23 4F Switchroom/Substation 23 4G Safety Precautions for Work on Low Voltage Installation 25 4H Safety Precautions for Work on High Voltage Installation 27 4I General Safety Practices 33 5. Segregation of Circuit Categories 35 5A Circuit Category 36 5B Segregation of Category 1, 2 and 3 Circuits 36 5C Segregation of Category 4 Circuits and Circuits of Other Categories 37 5D Segregation of Circuits from Overhead Telecommunication Lines and Telephone Lines 38 6. Circuit Arrangement 40 6A Division of Installation into Circuits 41 6B Basic Requirements of Circuits 41 6C Ring Final Circuit Arrangement 42 6D Final Circuits Using 5A or 15A Socket Outlets to Requirements Prescribed in Appendix 1 43 6E Final Circuits Using 13A Socket Outlets to Requirements Prescribed in Appendix 2 43 6F Final Circuits Using 5A, 15A or 30A Industrial Socket Outlets to Requirements Prescribed in Appendix 3 44 3 Page 6G Final Circuits Using 16A Industrial Socket Outlets to Requirements Prescribed in Appendix 4 45 6H Final Circuits Using 32A, 63A or 125A Industrial Socket Outlets to Requirements Prescribed in Appendix 4 45 6I Protection Requirement of High Voltage Circuit 45 7. Current Demand 52 7A Current Demand of a Circuit 53 7B Determination of Current Demand 53 8. Isolation and Switching 56 8A Provision of Isolation and Switching 57 8B Requirements of Isolation and Switching Devices 60 9. Overcurrent Protective Devices 64 9A General Requirements 65 9B Relation Between Circuit Conductors and Overcurrent Protective Devices 66 9C Breaking Capacity of Overcurrent Protective Devices 67 9D Position of Overcurrent Protective Devices 67 9E Other Requirements of Overcurrent Protective Devices 68 10. Neutral Conductor Protective Devices, Isolators and Switches 73 10A Linked Circuit Breakers, Linked Isolators and Linked Switches 74 10B Protection of Neutral Conductor 74 10C Single-pole Switch in Earthing Conductor 74 11. Earth Leakage and Earth Fault Currents 75 11A General 76 11B Basic Requirements 76 11C Protective Conductors 77 11D Earthing of Exposed Conductive Parts 78 11E Equipotential Bonding 79 11F Supplementary Bonding 80 11G Main Earthing Terminal 81 11H Earthing Conductor 82 11I Earth Fault Loop Impedance (Zs) 83 11J Residual Current Device (RCD) 83 11K Earth Electrodes 84 4 Page 12. Earthing Arrangement 93 12A General 94 12B Bonding Connections to the Point of Supply 94 12C Earth Electrode 95 13. Conductors, Joints and Connections 97 13A Selection and Sizing of Cable Conductors 98 13B Basic Protection 100 13C Joints and Connections 100 13D Other Requirements of Cables 101 14. Wiring Installation Enclosure 104 14A General Requirements 105 14B Steel Conduit System 105 14C Steel Trunking System 106 14D Plastic or PVC Conduit or Trunking 107 14E Cable Capacity of Enclosures 108 14F Enclosures of Busbar Trunking System and Powertrack System 109 14G Workmanship 109 15. Adverse Conditions Installation 113 15A Presence of Water (AD) or High Humidity (AB) 114 15B Ambient Temperature (AA) 115 15C Presence of Corrosive or Polluting Substance (AF) 116 15D Installation Exposed to Fire or Explosion 117 15E Impact (AG) 118 15F Vibration (AH) 119 15G Other Mechanical Stresses 119 16. Overhead Line Installations 125 16A General 126 16B Installation of Overhead Lines 126 16C Joints of Overhead Lines 126 16D Service to Building 126 16E Conductor to Ground Clearance 126 16F Pole 127 16G Stay Wire 127 16H Carrier Wire 127 16I Earthing of Metallic Parts and Earth Leakage Protection 128 5 Page 17. Display of Labels and Notices 129 17A Warning Notice for Substations and Switchrooms 130 17B Warning Notice for Connection of Earthing and Bonding Conductors 130 17C Warning Notice for Repair 131 17D Notice of Periodic Testing of Electrical Installations 131 17E Notice of Testing for Residual Current Devices 131 17F Warning Notice for Installation Having Both New and Old Cable Colours 132 18. Alterations and Additions 133 18A Requirements for Alterations or Additions to a Fixed Installation 134 18B Approval from the Electricity Supplier 134 19. First Inspection, Testing and Certification 135 19A Certification on Completion of an Installation 136 19B Work Completion Certificate 136 20. Periodic Inspection, Testing and Certification 138 20A Fixed Electrical Installations Specified in Regulation 20(1) 139 20B Fixed Electrical Installations Specified in Regulations 20(2), 20(3) and 20(4) 140 20C Periodic Test Certificate 141 21. Procedures for Inspection, Testing and Certification 142 21A Inspection of Low Voltage Installations 143 21B Testing of Low Voltage Installations 144 21C Inspection of High Voltage (H.V.) Installations 148 21D Testing of High Voltage Installations 149 21E Points to be Noted by Registered Electrical Workers 149 21F Power Suspension Arrangement for Periodic Inspection, Testing and Certification (PITC) Work on Main Switchboard connecting to Power Company’s Transformer 151 22. Making and Keeping of Records 159 22A Keeping of Records by the Owner of an Electrical Installation that Requires Periodic Inspection, Testing and Certification 160 22B Making and Keeping of Records by a Registered Electrical Contractor 160 22C Types of Records 160 22D Checklists 160 6 Page 23. (Reserved for Future Uses) 163 24. Part II 25. General Workmanship 164 25A Wiring Installation Using Conduits 165 25B Wiring Installation Using Trunkings 167 25C Installation of Cables 167 25D Cable Joint and Cable Termination 170 25E Installation of Socket Outlets 174 26. Requirements for Specific Installations and Equipment 180 26A Domestic Installation and Appliance 182 26B Busbar Trunking Distribution System 187 26C Electric Motor 189 26D Supply Connection to Transformers 190 26E Supply Connection to Welding Sets 191 26F Installation of Fluorescent and Gaseous Discharge Lamps 191 26G Installation of Category 3 Circuits 191 26H High Voltage Discharge Lighting Installation (Neon Signs) 191 26I Lightning Protection Installation 195 26J Rising Mains Installation 195 26K Temporary Supply Installation for Construction and Demolition Sites or Repair and Testing Purposes 195 26L Hot Air Saunas Installation 198 26M Swimming Pools and Fountains Installation 200 26N Installation in Restrictive Conductive Locations 205 26O Installation of Equipment Having High Earth Leakage Currents 207 26P Renewable Energy Power System 209 26Q Temporary Electrical Installation for Exhibitions, Shows, Stands and Festive Lighting 210 26R Electric Heating Systems installed in Building Structures 212 26S Charging Facilities for Electric Vehicles 212 7 Page Appendices 220 1. Prescribed Requirements for 3-pin (non-reversible) 5 ampere and 15 ampere Socket Outlets 221 2. Prescribed Requirements for 3-pin (non-reversible) 13 ampere Socket Outlets 229 3. Prescribed Requirements for Protected Type Non-reversible 5 ampere, 15 ampere and 30 ampere Socket Outlets 238 4. Prescribed Requirements for Industrial Type 16 ampere, 32 ampere, 63 ampere and 125 ampere Socket Outlets with Retaining Devices 248 5. Rating Factors for Sizing of Cable Conductors 264 6. Current Carrying Capacities and Voltage Drop Tables for PVC Insulated and XLPE Insulated Cables 268 7. Typical Methods of Installation of Cables 286 8. Graphical Symbols for Electrical Diagrams 290 9. Performance Monitoring Points System for Registered Electrical Workers / Contractors 298 10. Degree of Protection Provided by Enclosures (IP Code) 299 11. Forms of Internal Separations for Switchgear Assemblies 301 12. (Reserved for Future Uses) 303 13. Sample of Schedule of Test Results for Electrical Wiring and Checklists 305 14. References 325 15. Safety for Live Work 332 16. Sample of Permit-To-Work / Sanction-For-Test 335 17. Sample of H.V. Enclosure Log Book / H.V. Padlock Movement Log Book 339 18. New Cable Colour Code for Fixed Electrical Installations- Installation Guidelines 341 Index 347 8 ACKNOWLEDGEMENT The Electrical and Mechanical Services Department of the Government of the Hong Kong Special Administrative Region would like to express gratitude to the organizations listed below for their kind permission to reproduce materials from their copyright publications: — British Standards Institution (BSI) — The Institution of Engineering & Technology (IET) (as the joint copyright holder with BSI for BS 7671—IEE Wiring Regulations) — International Electrotechnical Commission (IEC) The organizations listed above retain the copyright on the reproduced materials which may not be reproduced without the prior written permission the organizations. Copies of the complete standards listed