Key elements of the AS3000 Wiring standards and some of the recent changes.

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1 Key elements of the AS3000 Wiring standards and some of the recent changes. Dean of Engineering Steve Mackay Worked for 30 years in Industrial Automation 30 years experience in mining, oil and gas, electrical and manufacturing industries 1

2 Practical Electrical Wiring Standards - AS 3000:2007 Overview In this module we discuss Course contents Background and importance of the standards and regulations AS/NZS 3000 preface Objectives of AS/NZS 3000 Contents of AS/NZS 3000 and main features 2

3 Total workshop outline Fundamentals of electrical distribution systems Common risks and hazards associated with Electricity use Safety norms and considerations to prevent and avoid such common hazards Basic requirements of AS/NZS: Wiring Rules Contents and stipulations of AS/NZS 3000 to ensure safe and reliable electrical installations Simple procedures / calculations as per AS/NZS 3000 related to main and earthing conductor sizes, maximum demand, voltage drops, etc. Mandatory checks and tests on an installation prior to energisation as per the standard. Need for the regulations Homogeneous regulations ensure availability of consumer items and their easy replacements or interchanges as and when needed, with minimum constraints. Helps in selection of correct and matching devices satisfying the expected performance needs. Ensure consistent quality and performance reliability for the equipments and installations. 3

4 Main objective of AS/NZS 3000 To define minimum requirements to be followed for the design, construction and testing of electrical equipment and installation in a safe manner so as to protect persons, livestock and property from electric shock, fire and physical injury hazards that may arise from the installation. Above objective is valid for new installations as well as for modifications/ additions to the existing ones How AS/NZS 3000 ensures safety? By providing Stipulations and practices to be followed for protection against risks and consequent hazards Requirements to be met by the system, equipments, accessories and installation to meet these stipulations and practices Mandatory verification and testing to ensure installation and equipments comply with the stipulated safety norms 4

5 Application areas Electrical installations in all types of premises and land used by electricity consumers. Reference for requirements relating to electrical installations in matters such as Safety of workplaces. (Occupational Health and Safety legislation and associated codes). Safe design/construction of buildings (like Building Code of Australia, New Zealand Building Code) Electricity generation, T & D systems. Safe connection to electricity distribution systems. Qualifications of electricity workers. AS3000:2007 edition Approved on behalf of the Council of Standards Australia and New Zealand and published on 12 th November Increased illustration diagrams on concepts and stipulations including additional practical examples based on feedback from 2000 edition users. Two parts with Part 1 (Section 1) covering Scope, application and fundamental principles and is generally complete in itself to avoid cross-referencing referencing to Part 2 (Sections 2-8). 2 Establish the deemed to comply status of AS/NZS 3018 relating to simple domestic applications 5

6 Some Important Changes Illustration of normal and alternative location of over current devices and its omission as well. Single main switch (per tariff) for a single domestic installation. Arc fault protection MUST for all switchboards with a nominal supply rated above 800 A Use of residual current devices (RCDs) to all socket outlet and lighting circuits up to 20 A Maximum three circuits connected to any one RCD. Voltage drop of up to 7% where a substation is located within the premises. Inclusion of additional appendices AS3000:2007 contents Part-1 aligned with IEC for essential safety. Part-2 (Sections 2 to 8) stipulates practices to be followed in the systems to achieve safety Failure to comply with a work method provision in Part 2 would breach high level safety conditions of Part 1 Alternative mechanism to Part-2 stipulations is acceptable subject to satisfying the objectives of Part -1. Testing and inspection provisions updated and aligned with AS/NZS 3017, including provisions for periodic inspection in accordance with AS/NZS

7 Section 1: Scope, application and fundamental principles Definitions for various electrical terms Protection requirements to minimize hazards Principles of protection Basic requirements for design and installation of electrical systems Requirements for new installations Requirements for additions and modifications to an existing installation Section 2 - General arrangement, control and protection Switchgear and controlgear arrangements for protection against hazards. Control of the electrical installation (or parts thereof) by suitable switching arrangements. Protection against fault conditions. Coordination of protective devices Design, selection and installation of switch boards. 7

8 Section 3 - Selection and installation of wiring system Protection against external influences and environmental conditions Steps to avoid mutual detrimental influences among multiple conductors Requirements to meet current-carrying carrying capacity, voltage drop, etc Practices for connections, joints and terminations to improve reliability Identification for safety and maintenance Fire protective measures Section 4 - Selection and Installation of appliances and accessories Installation requirements of motors, transformers, Capacitors, heating systems, lighting systems, UPS and standby sources, etc. to ensure protection against physical injury. protection from thermal effects. Safe and reliable circuit connection proper isolation and switching under abnormal conditions Protective devices and their features 8

9 Section 5 - Earthing arrangements & earthing conductors Protective and functional earthing Recommended earthing resistance values Mechanical protection appropriate to the assessed conditions of external influence Sizing and selection of earthing electrodes and conductors. Section 6 - Damp situations Safety concerns in damp areas Area classifications in bath rooms, showers, pools, fountains, saunas, etc based on level of safety needed. Selection and Installation practices for Electrical equipment in classified areas to achieve the desired level of safety 9

10 Section 7 - Special Electrical installations Safety services Electricity generation systems. Electrical separation systems. Extra-low voltage electrical installations. High voltage electrical installations. Explosive / Hazardous areas. Miscellaneous installations like Construction/ demolition sites, medical treatment areas, cranes/hoists, lifts, generating sets, carnivals, telecom network power supplies, etc Section 8 - Verification Minimum inspection and test procedures to check compliance of an installation to AS/NZS 3000 wiring rules before putting into service covering Inspection checklists. Mandatory tests Sequence of tests before/ after energisation Recommended results for acceptance 10

11 Appendices to AS/NZS 3000 A. Referenced Standards/ documents B. Circuit Protection Guide (circuit arrangements, protection coordination, etc) C. Circuit Arrangements (MD, voltage drop calculations, conduit limitations, etc) D. Posts, poles and structures for aerial line conductors E. National Building Code requirements F. Installation of Surge Protective Devices Appendices to AS/NZS 3000 G. Degrees of Protection (IP classification) of enclosed equipment H. Classification of wiring systems (WS) I. Protection devices for existing installations carrying out alterations. J. Symbols used in this standard K. Deleted (HV installation requirements) L. Shock survival guide Australia M. Shock survival guide New Zealand 11

12 Practical Electrical Wiring Standards - AS 3000:2007 Electrical Distribution Systems In this module we discuss Evolution of electrical distribution systems AC systems and DC systems Polyphase AC circuits Vectorial representations Advantages of three phase systems AC system connections HV and LV distributions systems Importance of Earthing Importance of Testing and verification Distribution systems in special locations 12

13 Energy Sources Conventional energy sources Involves a combustion process Depletion of natural resources like coal, oil, etc. Major Air Pollution contributors Non conventional/renewable energy sources Combustion process not a must Use sun, wind, etc. directly to produce power Bio degradable wastes also can be used Air pollution is avoided However conventional sources still rule the world Initial Distribution systems Considerations A source and a load Conductors that carry the load current from the source to the load Conductors S Source 13

14 Distribution systems Today Hundreds of large size power sources Millions of consumers and industry loads separated by long distances Multiple sources for continuity of power supply with interlocks and changeover schemes. AC and DC Power Direction of flow of electrons decide the type Initial inventions based on DC Power Generators comprise of conductors and magnetic field with relative motion that results in current flow in conductors AC power gained importance with Invention of transformers Advantages in Long distance transmission Easier conversion to DC 14

15 Three phase AC More power with three phase system compared to single phase system Economical advantage - Least conductor size to transfer 3 phase power Convenient and cost effective power generation from rotating generators with different prime movers AC vectors 15

16 3 phase AC vectors 3 phase connections 16

17 Protection Need for Protection Safety for persons/livestock Enhanced system life Safety from consequent hazards like fires, etc after faults Fault conditions High voltage and High currents Protections needed against over current and earth fault conditions in any system irrespective of the voltage Protection methods and fault currents impacted by earthing practices Need for earthing Basic safety ensured by keeping the contact surfaces of live systems at or near ground (zero) potential Permits easy fault detection using earth as a path for flow of currents from fault point to source thereby preventing catastrophic accidents 17

18 Earthing - Definitions Earth - The conductive mass of the Earth whose electric potential at any point is conventionally taken as zero. Protective Earthing - Connection of exposed conductive parts of an installation to the earth through earthing terminals to protect against direct and indirect contacts. Functional Earthing - Earth connection for proper functioning of equipment and not providing safety. Earthing Terminal - The terminal or bar provided for the connection of protective conductors, bonding conductors, and functional earthing conductors to the earth. Flow of Fault current 18

19 Protective earthing functions To reduce electric shock hazards to personnel. Sensing of fault current by a circuit protective device to safely isolate the faulty circuit from the power source Earth path of adequate rating and reduced let-through through energy by circuit protective devices minimize fire or explosion hazard Path for conducting away leakage capacitive currents and accumulated static charges. Entire LV installation as near earth potential as practicable when an accidental contact to a higher voltage system occurs to minimize hazards Common Electrical Hazards AS/NZS provides the regulations for protections against all the following hazards Thermal effects Over current (Overloads) and short circuit (Faults) Overvoltage Undervoltage 19

20 Thank You For Your Interest If you are interested in further training, please visit: The Engineering Institute of Technologies Online Certificate and Advanced Diploma programs: IDC Technologies 1, 2 & 3 day practical workshops, technical manuals, onsite training & International conferences: 20