Unit 01 electrical wiring diagrams

Electrical wiring

1. Subject: Electrical Estimating and Contracting Subject Code:22627 Subject Teacher: Ms.P.K.Chowdhary Lecturer, EE

2. Various COs achieved in the syllabus: Interpret various electrical diagrams. Prepare estimate of domestic and commercial electrical installations. Prepare estimate of industrial electrical installations . Prepare estimate of overhead and underground distribution lines. Prepare estimate of public lighting installations. Prepare quotation, tender and other related documents

3. Unit 01: Electrical Wiring Diagrams

4. Need of Electrical Symbols: Drawing is the language of engineers. For proper communication people must use the same language so that a particular word means the same thing to every one. In engineering drawing it is common practice to employ graphical symbols to denote the various accessories used. These symbols must convey the same meaning to everyone who reads the drawing. An electronic symbol is a pictogram used to represent various  electrical and  electronic devices or functions, such as wires, batteries, resistors, and transistors, in a  schematic diagram of an electrical or electronic circuit. These symbols are largely standardized internationally today, but may vary from country to country, or engineering discipline, based on traditional conventions .

5. Electrical Symbols used in diagrams as per Indian Standard:

6. Electrical Diagrams: Electrical diagram  is “an interconnection of electrical component symbols for a specific application”. Electrical diagrams play a vital role for physical connection of components in real time applications. The physical connection of electrical components without electrical diagram leads to failure in the system and damage of electrical components. Electrical diagram is like a preplan to the physical connection of components in real time applications. Consider one example of simple series RLC circuit in Figure 1 .

7. Classification of Electrical Diagrams: Electrical diagrams are classified depending upon the purpose as per IS: 2042 (Part-I)-1962 as follows: Wiring Diagram Circuit (Schematic) Diagram

8. Definition of Wiring Diagram: IS: 2042 (Part-I)-1962 defines a wiring diagram as: “The wiring diagrams are intended to guide the execution and checking of the internal and external, or both, connections of an installation or part of the installation. The drawings may sometimes show the layout of the different parts and accessories, such as terminal blocks, and the wiring between them.” Figure 1.1 below shows the wiring diagram of two lights controlled by two individual switches and one fan controlled by one switch and a fan regulator.

9. Definition of Circuit (or Schematic) Diagram: IS: 2042 (Part-I)-1962 defines a circuit diagram as: “The circuit (or schematic) diagram is an explanatory diagram intended to facilitate the understanding of the details of operation. It shows by symbols on an installation or part of an installation all the electrical connections concerned in its operation.” Figure 1.2 below shows the schematic diagram for the electrical circuit of wiring diagram of figure 1.1.

10. Methods of representation for the wiring diagram: A wiring diagram can be represented in two ways: Multi line wiring diagram Single Line wiring diagram

11. Methods of representation for the wiring diagram: It can be noted from figure 1.3 that those lines which run together in the multiline representation of figure 1.1 are in a single line representation represented by a single line. The number of wires is represented by an equal number of short thin slanting lines marked over the single line. If the number of wires running together is more than three, it is sufficient to draw only one slanting line over the single line and indicate by means of a figure the number of wires (figure 1.3). Several similar accessories mounted side by side in one place are represented by one single symbol along with a figure which indicates the number of such accessories used. This will be clear by reference to figure 1.3 where two switches have been represented by symbol for one switch and a number . In actual practice it is not usual to draw multi line wiring diagrams. Single line diagrams give sufficient information to the wireman to indicate the material required and to actually carry out the installation .

12. Examples on Conversion of Multiline diagram into Single line diagrams: Q1) Convert the multiline diagram shown in fig a below into its single line representation. Figure a: Multiline diagram

13. Solution: Fig b below represents the single line representation of the multiline diagram shown in fig a Figure b: Single line diagram

14. Q2) Convert the multiline diagram shown in fig c below into its single line representation. Figure c: Multiline diagram

15. Solution: Fig d below represents the single line representation of the multiline diagram shown in fig c Figure d: Single line diagram

16. Fundamental Principles for electrical installations: An electrical installation comprises all the fixed electrical equipment that is supplied through the electricity meter. It includes the cables that are usually hidden in the walls and ceilings, accessories (such as sockets, switches and light fittings), and the consumer unit ( fusebox ) that contains all the fuses, circuit-breakers and, preferably residual current devices (RCDs ).

17. Work Scope of a general Electrical Installation: Preparing Electrical Layout Drawings and Schematic Drawings based on Architectural Drawings Determine Electrical Specifications List out Material and Component requirements Decide Main Distribution Board locations Lay conduits in the building as necessary Install boxes for Switches and Sockets Install Distribution Boards and Main Switches Install Cables from Distribution Boards to Switches, Light/Fan points, and Socket outlets [receptacles] Install Earth Electrode for the Electrical System. Install Lights, Switches, Sockets and other accessories Test the Installation and obtain Test Certificate Obtain Service Connection from Power Utility Company Ready for Commissioning of the Electrical Installation .

18. Safety in Electrical Work: Following are the various safety requirements in electrical work as per Indian Electricity Rules 1956: Construction , installation, protection, operation and maintenance of electric supply lines and apparatus: All electric supply lines and apparatus shall be of sufficient ratings for power, insulation and estimated fault current and of sufficient mechanical strength, for the duty which they may be required to perform under the environmental conditions of installation, and shall be constructed, installed, protected, worked and maintained in such a manner as to ensure safety of human beings, animals and property. Service lines and apparatus on consumer’s premises: The supplier shall ensure that all electric supply lines, wires, fittings and apparatus belonging to him or under his control, which are on a consumer’s premises, are in a safe-condition and in all respects fit for supplying energy and the supplier shall take due precautions to avoid danger arising on such premises from such supply lines, wires, fittings and apparatus .

19. 3 ) Earthed terminal on consumer’s premises: The supplier shall provide and maintain on the consumer’s premises for the consumer’s use, a suitable earthed terminal in an accessible position at or near the point of commencement of supply. Provided that in the case of medium, high or extra-high voltage installation the consumer shall, in addition to the aforementioned earthing arrangement, provide his own earthing system with an independent electrode. Provided further that the supplier may not provide any earthed terminal in the case of installations already connected to his system on or before the date to be specified by the State Government in this behalf if he is satisfied that the consumer’s earthing arrangement is efficient. The consumer shall take all reasonable precautions to prevent mechanical damage to the earthed terminal and its lead belonging to the supplier.

20. 4) Danger Notices: The owner of every medium, high and extra-high voltage installation shall affix permanently in a conspicuous position a danger notice in Hindi or English and the local language of the district, with a sign of skull and bones on: (a) every motor, generator, transformer and other electrical plant and equipment together with apparatus used for controlling or regulating the same; (b) all supports of high and extra-high voltage overhead lines which can be easily climbed-upon without the aid of ladder or special appliances.

21. 5) Handling of electric supply lines and apparatus : Before any conductor or apparatus is handled adequate precautions shall be taken, by earthing or other suitable means, to discharge electrically such conductor or apparatus, and any adjacent conductor or apparatus if there is danger therefrom, and to prevent any conductor or apparatus from being accidentally or inadvertently electrically charged when persons are working thereon. Every person who is working on an electric supply line or apparatus or both shall be provided with tools and devices such as gloves, rubber shoes, safety belts, ladders, earthing devices, helmets, line testers, hand lines and the like for protecting him from mechanical and electrical injury

22. 6 ) Supply to vehicles, cranes, etc .- Every person owning a vehicle, travelling crane, or the like to which energy is supplied from an external source shall ensure that it is efficiently controlled by a suitable switch enabling all voltage to be cut off in one operation and , where such vehicle, travelling crane or the like runs on metal rails, the owner shall ensure that the rails are electrically continuous and earthed. 7) Cables protected by bituminous materials- Where the supplier or the owner has brought into use an electric supply line(other than an overhead line) which is not completely enclosed in a continuous metallic covering connected with earth and is insulated or protected in situ by composition or material of a bituminous character- any pipe, conduit, or the like into which such electric supply line may have been drawn or placed shall , unless other arrangements are approved by the Inspector in any particular case, be effectively sealed at its point of entry into any street box so as to prevent any flow of gas to or from the street box,; and such electric supply line shall be periodically inspected and tested where accessible, and the result of each such inspection and test shall be duly recorded by the supplier or the owner.

23. 8 ) Provisions applicable to protective equipment- Fire buckets filled with clean dry sand and ready for immediate use for extinguishing fires, in addition to fire extinguishers suitable for dealing with electric fires, shall be conspicuously marked and kept in all generating stations, enclosed sub-stations and switch stations in convenient situation. The fire extinguishers shall be tested for satisfactory operation at least once a year and record of such tests shall be maintained. First-aid boxes or cupboards, conspicuously marked and equipped with such contents as the State Government may specify, shall be provided and maintained in every generating station, enclosed sub-station and enclosed switch station so as to be readily accessible during all working hours. All such boxes and cupboards shall, except in the case of unattended substations and switch stations, be kept in charge of responsible persons who are trained in firstaid treatment and one of such person shall be available during working hours.

24. 9 ) Instructions for restoration of persons suffering from electric shock- Instructions , in English or Hindi and the local language of the District and where Hindi is the local language, in English and Hindi for the restoration of persons suffering from electric shock, shall be affixed by the owner in a conspicuous place in every generating station, enclosed sub-station, enclosed switch-station and in every factory. The owner of every generating station , enclosed sub-station, enclosed switch-station and every factory or other premises to which this rule applies, shall ensure that all authorised persons employed by him are acquainted with and are competent to apply the instructions. In every manned high voltage or extra-high voltage generating station, sub-station or switch station, an artificial respirator shall be provided and kept in good working condition.

25. 10) Intimation of Accident- If any accident occurs in connection with the generation, transmission, supply or use of energy in or in connection with, any part of the electric supply lines or other works of any person and the accident results in or is likely to have resulted in loss of human or animal life or in any injury to a human being or an animal, such person or any authorised person of the State Electricity Board/Supplier, not below the rank of a Junior Engineer or equivalent shall send to the Inspector a telegraphic report within 24 hours of the knowledge of the occurrence of the fatal accident and a written report within 48 hours of the knowledge of occurrence of fatal and all other accidents. Where practicable a telephonic message should also be given to the Inspector immediately the accident comes to the knowledge of the authorised officer of the State Electricity Board/Supplier or other person concerned.

26. 11) Precautions to be adopted by consumers, Owners, electrical contractors, electrical workmen and suppliers: No electrical installation work, including additions, alterations, repairs and adjustments to existing installations, except such replacement of lamps, fans, fuses, switches, low voltage domestic appliances and fittings as in no way alters its capacity or character, shall be carried out upon the premises of or on behalf of any 3 [consumer, supplier, owner or occupier] for the purpose of supply to such 3 [consumer, supplier, owner or occupier] except by an electrical contractor licensed in this behalf by the State Government and under the direct supervision of a person holding a certificate of competency and by a person holding a permit issued or recognised by the State Government.

27. 12) Periodical inspection and testing of installation: Where an installation is already connected to the supply system of the supplier, every such installation shall be periodically inspected and tested at intervals not exceeding five years either by the Inspector or any officer appointed to assist the Inspector or by the supplier as may be directed by the State Government in this behalf or in the case of installations belonging to, or under the control of the Central Government, and in the case of installation in mines, oilfields and railways by the Central Government. the periodical inspection and testing of high voltage and extra high voltage installations belonging to supplier, shall also be carried out at intervals not exceeding five years by the inspector or any officer appointed to assist the inspector. The fees for such inspection and test shall be determined by the Central or the State Government, as the case may be, in the case of each class of consumers and shall be payable by the consumer in advance. In the event of the failure of the owner of any installation to rectify the defects in his installation pointed out by the Inspector or by any officer appointed to assist him and authorised under sub-rule(2) of rule 4-A in the form set out in Annexure IX and within the time indicated therein, such installation shall be liable to be disconnected The consumer shall at all times be solely responsible for the maintenace of his installation in such condition as to be free from danger.

28. Safety instructions and safety practices: Actual safety requires whole hearted cooperation, from all levels of workers involved in the work. It is need not to say, that all the people engaged in the electrical work should well aware of all safety rules and regulations related to the work they are executing. The workers executing the work should be extremely disciplined. Electrical work should not be done by wearing loose dresses. Before starting the work, the working place should be made neat and clean. The place should also be sufficiently illuminated before work. All levels of voltage should be considered equally dangerous. Even the voltage levels which cannot produce electrical shock should also not be ignored. One shall first confirm the circuit is dead before touching it for repairing maintenance and any others works . We have to switch off, isolate and properly earth the circuit before doing any work with the circuit .

29. We shall only execute the work after getting properly issued work permit from the concerned operating personal. The work permit can only be issued after making the circuit completely dead, isolated and earthed. We must display  Danger Board  at the place of work. We should not allow any unauthorized person to enter in the working place. We should not put any new equipment into the service without necessary testing by authority. All electrical equipments , circuits , should be identified by properly viewable labels to avoid any mistake . We should not work on electrical circuit during heavy lightning storm. We should wear shoes having sewn soles, preferably insulated rubber soles. We should not toss the tools or working materials to other person. It is better to deliver the tools and materials hand to hand. We should not keep any tools at the edge of equipment cabinet or structure from where these may fall off .

30. Work Permit: What is a Work Permit? A work permit is a written form used to authorize the jobs that endanger workers to the serious hazards. It recognizes the work to be done, the hazards involved, and the necessary preparation and the precautions for the job. It has been noticed many a time that contractors engaged workforce that is not appropriately trained for the task or is competent enough to handle the jobs undertaken. " Permit to work” is one of the most significant tools, which if implemented effectively at site, meets or exceeds the established Health and Safety guidelines. A permit to work provides a systematic disciplined approach to access the risks of a job and specify the precautions to be taken when performing a job. Permit to work is issued by a supervisor to the contractor Permits are generally prepared in two-fold. One copy is handed over to the contractor performing the job and other is retained by the supervisors for records.

31. Permit to Electrical Work: An EEWP (Energized Electrical Work Permit) is the document that clearly describes the following: The circuit, the equipment, and the location of the job/task at hand. The work that is to be done. Justification of why the circuit or the equipment cannot be de-energized or the work deferred until the next scheduled outage . The EEWP document should also include the section for the Electrically Qualified Person to assess the task at the hand and determine if the job can be done safely. In order to do this he or she must be able to provide the following information: A detailed job description procedure to be used when performing the job/task at the hand. A description of the safe work practices to be employed. Results of the Arc Flash Hazard Analysis and the Shock Hazard Analysis. Shock Protection Boundaries. Necessary personal protective equipment to safely perform the assigned task. Means employed to the restrict the access of unqualified persons from the work area. Evidence of the completion of the Job Briefing including the discussion of any job-related hazards .

32. The document shall include the signatures (and dates) of the following personnel: Electrically Qualified Person performing the job/task at hand Manufacturing Manager Safety Manager General Manager Maintenance or Engineering Manager Electrically Knowledgeable Person Equipment Disjointing Certificate/Breaking Containment Permit Permit to Electrical Work:

33. National Electrical Code 2011: Electrical installations require adequate planning right from concept stage to layout and designing, selection of proper equipment, their installation and their maintenance. Fundamental aspects of installation practice are common for most of the types of electrical installations. The National Electrical Code covers these aspects under its various Sections.

34. National Electrical Code 2011: Part 1: General and Common aspects: Electrical installations require adequate planning right from concept stage to layout and designing, selection of proper equipment, their installation and their maintenance. Fundamental aspects of installation practice are common for most of the types of electrical installations. Part 1 of the National Electrical Code covers these aspects under its various Sections.

35. National Electrical Code 2011: Part 1: General and Common aspects :

36. National Electrical Code 2011: PART 2: ELECTRICAL INSTALLATIONS IN STAND-BY GENERATING STATIONS AND CAPATIVE SUBSTATIONS: This National Electrical Code (Part 2) is primarily intended to cover the requirements relating to stand-by generating stations and captive substations intended for serving an individual occupancy. As the general provisions relating to such installations are common and are themselves elaborate in nature, it was felt essential to cover them in a separate part preceding the other parts which cover the requirements for specific installations. Generating stations covered by this Part 2 are the stand-by or emergency supply and captive substations normally housed in or around the building in question.

37. National Electrical Code 2011: PART 3: ELECTRICAL INSTALLATIONS IN NON-INDUSTRIAL BUILDING : For the purposes of this Code, electrical installations in buildings have been broadly classified as those in non-industrial and industrial . While a majority of installations could be categorically classified as nonindustrial, an industrial complex would necessarily incorporate sub-units such as offices, residential quarters and support services which are either housed or fall in the category of non-industrial buildings. The requirement stipulated in Part 3 and Part 4 of this Code would therefore require judicious application.

38. National Electrical Code 2011: PART 4: ELECTRICAL lNSTALLATlONS IN INDUSTRIAL BUILDING: Electrical networks in industrial buildings serve the purpose of distributing the required power to the consuming points where it is used for a multitude of purposes in the industry. The design of electrical installation in industrial premises is therefore more complicated than those in non-industrial buildings. Industrial installation has to take care of load requirements and supply limitations in a simple and economic manner, ensuring at the same time full protection to human life and loss of property by fire. The network layout should also facilitate easy maintenance and fault localization. PART 5 : OUTDOOR INSTALLATIONS: As compared to the various types of indoor installations covered in other Parts of this Code, outdoor installations are distinct in nature by virtue of their being exposed to moderate to heavy environmental conditions. In addition, electric power in outdoor installations is normally utilized for specific purposes such as, lighting or for meeting the needs of heavy machinery (example, open cast mines).

39. PART 6: ELECTRICAL INSTALLATIONS IN AGRICULTURAL PREMISES : This Part of the Code is primarily intended for covering the specific requirements of electrical installations in agricultural premises which include premises where livestock are present and farm produce are handled or stored. With the increase in sophistication in organising the farm output of the country, and the use of electricity for certain essential purposes, it has been felt necessary to cover the requirements of such installations as a part of the Code. PART 7: ELECTRICAL INSTALLATIONS IN HAZARDOUS AREAS: This Part 7 of the Code is intended to provide guidelines for electrical installations and equipment in locations where a hazardous atmosphere is likely to be present, with a view to maximising electrical safety. The scope of this Part therefore includes installations in hazardous areas such a petroleum refineries and petrochemical and chemical industries. PART 8: SOLAR PHOTOVOLTAIC (PV) POWER SUPPLY SYSTEMS: This Part 8 of the Code covers essential requirements for electrical installations for power supply system based on the solar photovoltaic energy including systems with ac modules. Solar energy is a natural resource which is, for practical purposes, free, renewable and inexhaustible and can supplement/augment the depleting fossil fuel resources. Greenhouse gases and pollutant emissions which result from fossil fuel generation can be offset by solar photovoltaic power generation. It can be used in decentralized/ distributed mode. National Electrical Code 2011:

40. Scope of National Electrical Code 2011: The National Electrical Code covers the following: Standard good practices for selection of various items of electrical equipment forming part of power systems; Recommendations concerning safety and related matter in the wiring of electrical installations of buildings or industrial structures, promoting compatibility between such recommendations and those concerning the equipment installed; General safety procedures and practices in electrical work; and Additional precautions to be taken for use of electrical equipment for special environmental conditions like explosive and active atmosphere.

41. Scope of National Electrical Code 2011: 2) The Code applies to electrical installations such as those in: Standby/emergency generating plants and building substations; Domestic dwellings; Office buildings, shopping and commercial centres and institutions; Recreation and other public premises; Medical establishments; Hotels ; Sports buildings; Industrial premises; Temporary and permanent outdoor installations; Agricultural premises; Installations in hazardous areas; and Solar photovoltaic installations.

42. Scope of National Electrical Code 2011: The Code applies to circuits other than the internal wiring of apparatus. The Code does not apply to traction, motor vehicles, installations in rolling-stock, on board-ships, aircraft or installations in underground mines. The Code covers only electrical aspects of lightning protection of buildings and in so far as the effects of lightning on the electrical installations are concerned. It does not cover lightning protection aspects from structural safety point of view. The Code is also not intended to apply to: a) Systems of distribution of energy to public; and b) Power generation and transmission for such systems. The Code also does not cover guidelines on the payment for electrical work done in installations.

43. Features of National Electrical Code 2011: ‘National Electrical Code India’ aims at focusing various provisions related to electrical installation practices in India . The code complemented and elaborated on the Indian Electricity Rules, 1956 for the ease of application by the system engineers by recommending the best practices for electrical installations in a consolidated form in order to provide for unified practices and procedures along with consideration for safety and economic usage of energy in the design, execution, inspection and maintenance of electrical installations of various locations . The Code is divided into eight parts, which are further divided into sections. Part 1 covers the General and common aspects, which would apply to all types of electrical installations. It covers the requirements relating to standby or emergency generating stations and captive substations intended for serving an individual occupancy and intended to serve a building or a group of buildings normally housed in and around it. It gives guidelines on layout and building construction aspects, selection of equipment, transformer installations, switching stations and station auxiliaries. Reference to pollution norms as laid down in Environment Protection Act 1986 for diesel generator sets has now been included. NEC provides guidelines for electrical installations and equipment in locations where a hazardous atmosphere is likely to be present with a view to maximizing electrical safety.

44. Features of National Electrical Code 2011: The National Electrical Code is intended to be advisory. It contains guidelines, which can be immediately adopted for use by the various interests concerned. Its provisions are presently not mandatory but are expected to serve as a model for adoption in the interest of safety and economy and with the intent to keep our electrical installation practices at par with the best practices in the world.

45. Types of Electrical Installations: Electrical installation can basically be characterized into two types Non Industrial electrical installations and Industrial electrical installations

46. Non Industrial Electrical Installations: Non Industrial Electrical Installations cover the following categories: 1) Domestic Dwellings : Electrical installations in domestic dwellings and in buildings providing living accommodation for people are by far the simplest form of installation. Use of electrical appliances, both portable and fixed has now become very common and popular even in single family dwellings. Domestic installations are characterized mainly by a circuit voltage of 250 V to earth except in the case of large power consumers where three-phase supply is given. 2) Office Building, Shopping and Commercial Centres and Institutions: Office buildings, shopping and commercial centres can be of various types depending on the size of the civil structure or the extent of activity involved in the building. High-rise buildings housing office complexes are common, calling for a coordinated planning while designing the electrical services therein . In small buildings with comparatively moderate loads, supply is normally at medium voltage and the distribution of power is less complex. However, in the case of multi-storied office-cum-commercial complex, where the large number of amenities is to be provided calls for a more complex distribution system .

47. Non Industrial Electrical Installations: 3) Recreational , Assembly Building: A variety of buildings are being used for public assembly for purposes that are recreational, amusement, social or religious. These include cinema halls, theatres, auditoria and the like, the primary feature being a congregation of people of all age groups for a short period of time during a day or a group of days. Buildings such as those catering to display of regular programmes demands a continuous power supply. In view of the nature of use of such occupancies, certain specific safety and reliability considerations become necessary for the electrical installations. The lighting design of such buildings are generally sophisticated, required to be properly coordinated with the electro-acoustic demands . These shall include any building where groups of people congregate or gather for amusement, recreation, social, religious, patriotic, civil and similar purposes, for example, theatres, motion-picture (cinema) houses, assembly halls, auditoria, exhibition halls, museums, restaurants, places of worship, dance halls, clubs, etc.

48. Non Industrial Electrical Installations: 4) Medical Establishments: Hospitals in the country vary in size from simple premises used for medical purposes in villages to a well-equipped, multidisciplinary hospital in big cities. The latter type will have several units functioning simultaneously with a variety of support services to cater to the needs of doctors and patients . Various medical rooms such as Anaesthetic Room, Central Monitoring Room, Delivery Room, Central Sterilization Room, Intensive Care Room, Radiological Therapy Room, Operating Theatre, Physiotherapy Room, Ward, etc require special electrical installation requirements which are included in this category.

49. 5) Hotels: Hotels lodging or rooming houses are of a wide variety, ranging from simple dormitory type accommodation for guests, where only a common bath is provided with no facility for dining/kitchen to the sophisticated star hotels. Increasing competition in the hotel industry as such, coupled with the demand by guests for a variety of comforts, calls for an electrical installation in a hotel with increased sophistication. The electrical needs of a hotel depend on the type and extent of facilities being provided and the rating of the hotel. The electrical installations in hotels include the following services: Supply intake, Main distribution centre , Ventilation and exhaust systems, Kitchen , Laundry , Cold storage, Swimming pool and filtration plants, Restaurants and bars, Interior lighting, Telephones , Service lifts and passenger lifts , Fire protection and alarm systems, Banquet halls and conference facilities, Gardens and parking lots and illumination systems therein, Non Industrial Electrical Installations:

50. Non Industrial Electrical Installations: 6) Sports Buildings: The design and erection of electrical installation in a sports building have to take into account a multitude of factors that are unique to the type of use to which it is put. In a way the electrical power needs and the external influences in a sports building are quite identical to those for theatres and other multipurpose buildings for cultural events excepting that for international events exacting standards of services and flexibility had to be provided in a multipurpose sports stadia. Several stadia, especially those of the indoor type are meant for staging a variety of games which between themselves require varying standards of lighting levels. The type of building shall therefore be classified as follows: Based on type of building: 1) Indoor stadia. 2) Outdoor stadia: Stadia meant for use in daylight. Stadia meant for use during night under artificial lighting. Based on type of game/sport: 1) Single game sports hall/stadia. 2) Multigames hall/stadia. Based on utility: 1) Stadia meant for games only. 2) Multipurpose stadia for other amusements as well. Based on audience-factor: 1) Stadia/halls meant for exhibition purposes — where groups of people congregate. 2) Stadia/halls meant for training and passtime — where audience may not normally be present.

51. Non Industrial Electrical Installations: 7) Specific Requirements for Electrical Installations in Multistoried Buildings: The design and construction of electrical installations in multistoried buildings call for special attention to details pertaining to fire-safety of the occupancy. While on the one hand, the civil design aspects are more stringent for high-rise buildings than for buildings of low heights, the electrical design engineer, on his part had to ensure that the fire hazards from the use of electric power is kept to the lowest possible limit. Special considerations shall have to be given in respect of the following requirements for the electrical installations in multistoried buildings: Internal wiring for lighting, ventilation, call bell system, outlets for appliances, power and control wiring for special equipments like lifts, pumps, blowers, etc ; Distribution of electric power; Generators for standby electric supply; Telephone wiring; Fire safety; Lightning protection; Common antenna system; Clock system; Building Management System (BMS )

52. Industrial Electrical Installations: Electrical networks in industrial buildings serve the purpose of distributing the required power to the consuming points where it is used for a multitude of purposes in the industry. The design of electrical installation in industrial premises is therefore more complicated than those in non-industrial buildings. Industrial installation has to take care of load requirements and supply limitations in a simple and economic manner, ensuring at the same time full protection to human life and loss of property by fire. The network layout should also facilitate easy maintenance and fault localization. Keeping in view the tariff structures as also the economic necessity of conserving power to the maximum extent, power factor compensation assumes special importance. A particular feature of electrical installations in industrial buildings is the reliability of supply to essential operations for which standby and emergency supply sources/networks had to be designed. The needs of such systems would depend on the type and nature of the industrial works. Locations in industrial buildings which are by their nature hazardous, require special treatment in respect of design of electrical installations therein.