Electrical Safety and Disaster Management PDF

Electrical Safety and Disaster Management In the previous unit, you have learnt about the Indian Electricity Rules, the safety procedures that need to be practised in all work related to electric supply and the earthing practic...

Electrical Safety and Disaster Management In the previous unit, you have learnt about the Indian Electricity Rules, the safety procedures that need to be practised in all work related to electric supply and the earthing practices that ensure safety while working with electricity. In this unit, we elaborate on the accidents that may occur if the safety procedures are not followed strictly. We describe the causes of accidents and discuss the general measures that can be taken for preventing and handling them. Personnel working in power utilities can safeguard themselves by following these measures. We focus on cases of electric shock and fire − the most serious kind of accidents that can take place in power utilities. Finally, we acquaint you with the first aid techniques. Some of these may be demonstrated in video-conferencing sessions so that you could assist the accident victims, if any such situation arises in your surroundings. We have put some safety slogans given in the DRUM material at various places in this unit. Pay attention to them. In fact, you could coin your own slogans and put them up in your work place! In the next unit, we take up disaster management for the handling of graver situations that may arise in the face of natural disasters and calamities. You will agree that ensuring safety at your work place is a critical dimension of your responsibilities. Accidents can change the lives of the victims and their families. Moreover, they can lead to heavy losses of lives and equipment, and prove to be costly and time consuming for you and your utility. From time to time, we all make mistakes, but when life and limb are at risk, it is inexcusable to take chances. It would be very sad to go through the rest of one’s life knowing that some one had been killed or injured due to one’s own negligence. Fortunately, most accidents in electrical installations can be avoided with a little care and caution. You only need to follow certain basic guidelines and procedures to prevent and reduce the incidence of accidents. Electrical accidents, unlike most other industrial accidents, quite often happen to professional and supervisory staff. In fact, in some situations, they may be at greater risk than the manual staff. Although the apparatus and working practices are undergoing change, many of the old problems persist, and we witness the same electrical accidents time and again. Therefore, we need to be more vigilant and careful. Let us begin the discussion by considering this question: What kinds of accidents take place in electrical installations? These are listed in Box 7.1. 42  Box 7.1: Types of Accidents Accident Prevention and Protection ELECTRIC SHOCK ELECTROCUTION BURNS (ELECTRICAL OR THERMAL CONTACT) FIRES EXPLOSIONS INJURY FROM A FALL, FROM CUTS, OR FROM FRACTURES Some points to be noted about electrical accidents are given below. Study them and then answer SAQ 1. A very large proportion of accidents to electrical staff do not involve electric shock but are caused by flash and arc burns due to incorrect way of working on live exposed conductors. Too much work is done live, and by persons with inadequate training in live work. Most electrical fatalities are due to electric shocks at the lowest distribution voltage of 240 V (415 V, 3 phase). Contrary to some commonly held beliefs, 240 V is a very dangerous voltage. Nearly all electric shocks, even at 240 V are potentially lethal. For every fatality, there have been many narrow escapes and far greater number of minor shocks and tingles. It depends crucially on whether the victim is able to ‘let go’ of the live conductors or not. Mostly the answer is yes, hence the large number of lucky escapes. !" Find out the number of accidents that have taken place in your utility in the last 5 years. Classify them into various categories listed in Box 7.1. ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… In order to prevent accidents in electrical installations, you first need to understand why accidents take place. 7.2.1 Causes of Accidents Let us begin by considering an example of how an accident can take place when a technician is working to rectify a fault. Suddenly, the rung of the ladder he is standing on breaks down, and he falls on the ground. His arm is fractured but luckily he does not sustain any serious head injury. 43 Electrical Safety and The question before us is –”Why did this happen?“ Disaster Management There could be many reasons for such an accident, some related to equipment and others related to safety procedures. Consider the following questions that may help you in arriving at a suitable answer: How do we design our ladders or other relevant equipment such as access stairs and platforms? How do we purchase ladders? Do we buy the cheapest available? Are they checked on arrival, for suitability? Are ladders stored in a controlled manner? Have we included ladders in our maintenance programme? Questions related to safety procedure would be: Do we have safety rules for using ladders and working at heights? Have people been trained in those safety rules? Are ladders properly marked and identified? Do we have any sort of an inventory control of ladders? Are people adequately supervised, particularly when performing risky tasks? The reason for this accident could stem from any one of the following factors: The issue of ladder safety is one of the least important in the safety management system. Ladder safety may be addressed but the standard of performance is inadequate. Standards may be defined but there is no compliance. This example is a pointer to the causes of accidents, which may be broadly divided into two categories: Direct and Indirect. Direct Causes of Accidents Accidents occur due to both unsafe acts of workforce and unsafe working conditions. Unsafe acts refer to the violation of commonly accepted safe procedures of working. Unsafe conditions refer to the conditions with potential of causing injury to a person or damage to the equipment. In Table 7.1, we give examples of both kinds of accidents. 44 Table 7.1: Examples of Accidents Arising from Unsafe Acts and Unsafe Accident Conditions Prevention and Protection EXAMPLES OF UNSAFE ACTS Operating without authority or unauthorized persons working on lines/ equipment. Failure to ensure safety, e.g., due to violation/ neglect of safety measures/ lack of supervision, following unsafe procedures and working without using safety appliances, etc. Bypassing safety devices. Use of unsafe tools/tackles. Unsafe loading and placing. Working on moving machinery/equipment. Working without obtaining proper line clear. Working without proper instructions from superiors. Wrong instructions from person who received the line clear. Lack of knowledge on feeding arrangements. And above all, negligence, carelessness, haste and overconfidence. EXAMPLES OF UNSAFE CONDITIONS Unguarded or defective machines. Unsafe design/construction. Improper illumination. Poor house-keeping. Lack of proper tools. Slippery floor. Snapping of conductors. Accidental contact with live electric wire/equipment. Defective appliances/apparatus/ tools. Inadequate maintenance or lack of maintenance. Unauthorized work, etc. 45 Electrical Safety and Disaster Management Fig. 7.1: Some Direct Causes of Accidents Indirect Causes of Accidents These comprise all such factors that give rise to direct causes. These include lack of knowledge and skills, physiological/anatomical deficiencies and inappropriate psychological traits of workers. Lack of knowledge and skills is marked by incorrect knowledge, incomplete knowledge, low degree of skill or lack of skill and misunderstanding of job instructions. Inappropriate physiological/anatomical deficiencies refer to poor eye- sight, hearing defects, lack of fitness, illness, allergies, etc. Inappropriate psychological traits characterize workers who are arrogant, lazy, fearful, careless, nervous, egoistical, absent-minded and over-confident. Fig. 7.2: Avoid Indirect Causes of Accidents − Acquire Knowledge and Skills, Adopt the Right Attitude and Overcome Deficiencies REMEMBER: INTOXICATION AT WORK CAN LEAD TO SERIOUS ACCIDENTS AND SHOULD NEVER BE PERMITTED. 46 At this stage, you may like to bring your own experiences into the discussion. Accident Prevention and Protection # !" Recall an accident that occurred in your workplace or at another electrical installation. What were the causes of the accident? List them and classify them as direct and indirect. ……………………………………………………………………………………… 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 7.2.2 Accident Reporting and Investigation supply lines or other works of any person Accident records are essential aids for prevention of accidents. They give us and the accident results in or is likely to information about the type of accidents most frequently encountered, where have resulted in loss they occur and their relative severity. A study of these records reveals of human or animal common hazards and leads to a better understanding of the causes of life or in any injury to a human being or an accidents and most effective methods of preventing them. animal, such person or any authorized All accidents should be promptly reported, whether they result in injury or person of the State not. Many injury-free accidents, which are not reported, recur with Electricity Board / serious injuries. All accidents to the public involving company personnel, Supplier, not below the rank of a Junior equipment or property should also be reported promptly. You have learnt Engineer or equivalent about Rule 44A of the Indian Electricity Rules, 1956 pertaining to the should send to the intimation of an accident. It is stated again in the margin for ready reference. Inspector a telegraphic report As per the rule the report should be submitted in a prescribed form, which is within 24 hours of the knowledge of the given in the Appendix 1. You must understand that the occurrence of electrical occurrence of the fatal accident has to be reported with all seriousness: It helps in ascertaining the accident and a written causes of electrical accidents. Besides, immediate steps can also be taken for report in the prescribed proforma administering first-aid, medical attendance, preserving the evidence, etc. A within 48 hours of the thorough review can be done on how the accident occurred, pinpoint lapses knowledge of and fix responsibilities. Measures can then be taken so that it does not recur. occurrence of fatal or Of course, it needs to be ensured that the remedial measures are all other accidents. Where practicable a implemented properly. telephonic message should also be given For breach of Rule 44A, there is penalty under Rule 138A of I.E. Rules, 1956 to the Inspector under which if any person responsible for the generation, transformation, immediately after the transmission, conversion, distribution, supply or use of energy fails to report to accident comes to the knowledge of the the Inspector and other authorities concerned, the occurrence of the authorized officer of accidents, s/he should be punishable. the State Electricity Board / Supplier or Every accident should be investigated to determine the cause and the other person steps needed to prevent its recurrence. It should be the responsibility of concerned. the person in charge of the work to get complete details of the accident as soon as possible after it occurs. Depending upon the seriousness of the 47 Electrical Safety and accident, apart from any statutory investigation of the accident, the Disaster Management management may like to have internal investigation conducted for the following purposes: arriving at factual information leading to corrective action; fact finding and not fault finding; identification of principal source of accident; indicating the need for engineering revision in various types of equipment and materials; and disclosure of inefficiencies in operating processes and procedures. However, it must be ensured that the investigating individual should not be involved with any disciplinary proceedings. 7.2.3 Cost of Accidents All injury cases, whether minor or major, result in financial loss to the organization in addition to irreparable loss for the family members in case of a fatal accident. The cost of accidents comprises two components: Direct cost and Indirect cost. Direct costs include the − cost of medical treatment; and MEDICAL − compensation for loss of earning capacity/permanent disability/fatality Indirect costs pertain to: − production loss and time loss of co-workers; − idle time of machine and damage to equipment; − loss of morale of workers in the unit; LEGAL − loss of time of supervisory personnel in submitting report/accident analysis; − loss of efficiency of injured persons after reporting for duty; − transportation charges; − administrative and legal expenses; − company’s reputation being at stake; − cost of training the substitute employee; PERSONAL − business interruption and failure to meet schedule; and Fig. 7.3: Some Costs − investigation by statutory authorities and penalties imposed by them. of Accidents Indirect costs usually vary from 5 to 11 times that of direct cost. 48  Accident $ !"% % "!&'!( "& " ! ! " Prevention and Protection Obtain the details of an accident that occurred in an electrical installation. Evaluate the accident reporting and investigation procedures followed and determine the costs involved in the light of the information given to you. $ ) * The art of electrical accident prevention has been founded primarily on the investigation of accidents by professionally qualified engineers. The science of accident prevention is based on a logical analysis of their reports. It takes great skill and determination to steer an organization into a safer regime. At the very least it requires the best possible information feedback from the workplace where the hazards exist. This requires attention to be paid to various audit and management information controls. A utility should have a contingent plan and system for dealing with any emergency. It should clearly spell out the purpose and scope, and the activities to be undertaken in case of emergencies (Box 7.2). Box 7.2: Emergency Preparedness and Response PURPOSE Establishing a system for dealing with emergency situations to minimize hazards to human health and safety. SCOPE Applicable to any fire, explosion or other disaster leading to emergency situation, which means, any significant on-routine situation, which endangers the personnel, property, other interested parties or surrounding environment. These may arise as a result of explosion, fire, etc. For personnel injuries/ medical emergencies, separate procedures need to be followed. ACTIVITIES Identify potential accident conditioned emergency situations for the activities in different departments in consultation with the concerned supervisor/Head of Team. Make all concerned personnel aware of the significant risk attached to their area of work that may lead to emergency situation. Discuss the situations with concerned team head and make emergency plans. Check the emergency preparedness and response to such situations and clearly identify responsibilities while preparing emergency plans. Provide controls for and mitigate the safety hazards associated with the activity. Train the personnel in dealing with emergency situations as per the emergency plan − by carrying out periodic drills, i.e., mock-drills/fire drills, etc. (at least once a year), creating emergency situations and keeping records. 49 Electrical Safety and One particularly useful management tool is to collect and analyze data on all Disaster Management ‘near miss’ incidents. There are many more of these than there will be of actual accidents. Provided that one can get those involved to be forthcoming about these incidents, a great deal of useful information can be gathered about an organization’s robustness and fitness to prevent accidents. It is likely to be much more revealing than trying to identify the weaknesses after the accidents themselves. The prevention of accidents is actually much more important than the technical discipline of identifying risk and adopting the right technical solutions to counter those hazards. It is also important from the point of view of the costs involved. You may also like to know: What can you do as an individual? You have studied about many safety procedures in Unit 6. You may like to quickly review them before studying further. You will agree that the best method of prevention of accidents is training, retraining and more training. We now spell out some measures that can help in the prevention of electrical accidents. One of the best ways to prevent an accident is to think ahead. As you plan your job, take a moment to identify any potential hazards. Are you working near overhead lines? Could there be cables buried nearby? Are your tools in good condition? Taking the necessary time to plan a job may help avoid later problems caused by an accident. This approach supplemented by observing safe practices should go a long way in preventing accidents. We now describe some good housekeeping precautions that can help prevent accidents. 7.3.1 General Measures for Preventing Accidents Workmen are frequently injured due to stumbling, stepping on, or bumping into tools, material and other objects left lying around, or by objects falling from above. Such incidents can be prevented by observing the following measures: walks, staircases, fire escapes and all other passages should be kept free Fig. 7.4: Keep Passages of all obstructions (Fig. 7.4); Clear! tools and materials should not be placed where they may cause tripping or stumbling hazards or where they may fall and strike anyone below; puddles of oil and water create slipping hazards and should be cleaned up promptly; nails in boards (such as those removed from scaffolds, forms and packing boxes) constitute hazards. These should be removed and the boards should be carefully stacked or stored; and dirty and oily waste rags should be deposited in approved containers and disposed off as soon as practicable to avoid fire hazard. 50  Accident Prevention and Protection Fig. 7.5: Some Possible Sources of Injury and Preventive Measures Other general housekeeping measures that need to be taken are as follows: broken light bulbs, glass metal and scrap and other sharp objects should be disposed off properly in containers provided specially for them; discarded fluorescent and other gas filled tubes should be disposed off safely; places where persons work or pass in emergencies, should be provided during time of use with adequate lighting (natural/artificial/or both) for operations or special type of work performed; general lighting should be of a uniform level widely distributed; emergency lighting should be provided in big installations/offices; and adequate ventilation should be provided in work places by natural/artificial means. Personal Protective Equipment (PPE) and Devices The utility should provide adequate and approved PPE for various jobs depending upon the hazard. Protective gears such as helmets, safety shoes, Fig. 7.6: Good safety “Rassi-Zolis” should be issued to linesmen, jointers, supervisors etc. Housekeeping is a STRAIGHT and their usage should be monitored. It is the responsibility of the supervisor Line to Safety to ensure the usage of PPE. You have learnt in Unit 6 that personnel have to use suitable protective equipment, like rubber gloves, mats, safety glasses, etc., wherever required as per instructions or wherever it provides greater safety. 51 Electrical Safety and In addition, the following rules should be observed for the use and care of Disaster Management PPE: use the appropriate PPE for the work being performed and the environment in which you are working; visually inspect and/or test PPE before use. Any defective or damaged PPE should be repaired or discarded and replaced; wear a protective outer covering (such as leather) in cases where the insulating capabilities of the PPE may be damaged during the work; wear non-conductive head protection wherever there is a danger of injury from electrical burns or shock caused by contact with exposed, energized parts; wear protective eye/face equipment whenever there is a danger from electrical arcs or flashes, or from flying objects as a result of an electrical explosion; do not carry/store PPE with tools or other objects to avoid damage to them; Fig. 7.7: Some Examples any employee working on height above 8 feet from ground except working of PPE on platform should use Safety Belts / Rassi; use only approved type of operating rods; keep operating rods as dry as possible. These should not be dropped / left lying on ground. Fig. 7.8: Use PPE 7.3.2 Proper Handling of Equipment Many accidents can be prevented if the instructions for proper handling of tools and appliances, ladders, earthing devices, etc. are followed. We describe these, in brief. 52 Tools and Appliances Accident Prevention and Many accidents result from improper use of tools as well as use of defective Protection tools and equipment. Employees should use only those tools and equipment, which are in good condition, and only for the purpose for which they are designed. Where proper and safe tools are not available for the work at hand, employees should report the fact to their supervisor. The following instructions should be followed: use proper tool for proper job. Ensure that every tool or appliance (e.g., slings, pulleys, chain block, etc.) is in good working condition; discard all non-working tools / appliances, damaged pipes, spanners, hammers, etc.; and remove tools, which develop defects while in use, from the service, tag them and do not use them until they are brought back in good condition. DO NOT USE impact tools such as chisels, drills, hammers and wedges with mushroom heads until they have been reconditioned; hammers, axes, shovel and similar tools if handles are loose, cracked or Fig. 7.9: Use Proper Tools splintered; defective wrenches such as open end and adjustable wrenches with spread jaws or pipe wrenches with dull teeth, as they are likely to slip; and pipes or other extensions on a wrench handle to increase the leverage unless the wrench is specifically designed for such an extension. INSPECT ALL TOOLS CARRIED ON TRUCKS EACH MONTH AND REPAIR/REPLACE DEFECTIVE TOOLS. Ladders The following safety measures need to be taken while using ladders: inspect the ladder before use; secure the ladder at top or station a person at its foot; ensure that ladders are used with a slope of about 75 degrees or position ladder 30 cm (1 foot) out at base for every 1.2 m (4 feet) of vertical height; ensure that the ladder rises 3 feet above landing point; Fig. 7.10: Use Ladders Properly face the ladder when climbing or descending and use both hands; 53 Electrical Safety and avoid make-shift arrangement in lieu of ladder; Disaster Management ensure that there are rubber shoes at both arms and at each terminal, i.e., at each end of the ladder; before fixing the ladder, confirm that no electrically charged conductor is passing nearby; and ensure that only one person uses the ladder at a time and another person keeps a watch on the ladder position. Earthing Devices Make sure that only approved earthing devices are used in all work; care is taken to maintain earthing by ensuring condition of clamps; neon line tester is used to check the bus bar area, cables, overhead conductors and it is ensured that the tester is in good condition. PROTECTIVE BARRIER (TEMPORARY) When the work is conducted along public streets or highways, pedestrian and vehicular traffic should be warned by signs and flags by day and red lights or flares by night. Wherever necessary, signalmen should be provided. Adequate steps should be taken for public safety. INSTRUCTIONS FOR SAFEGUARDING THE PUBLIC Every effort should be made to protect the public at all times where the company’s work is in progress by the use of signs, barricades or personal warning. When working on customer premises or public property, every effort should be made to avoid hazards to persons or unnecessary property damage. Barriers should be placed around all open manholes, exposed open ditches and excavations. Authorized visitors should not be left to find their own way. Public should be encouraged to report dangerous situations which may come to their notice. Visitors should be provided proper personnel protective equipments wherever required. 54  Accident + !" %( !" ! Prevention and Protection Refer to the details of the accident you have described in SAQ 3. How could the accident have been prevented using the general measures described in this section? ……………………………………………………………………………………… ………………………………………………………………………………………. We now highlight best practices for personal safety while working in electrical installations. As a supervisor or a manager, it is your responsibility to make sure that these are strictly observed. BEST PRACTICES FOR PERSONAL SAFETY DOs Use proper tools for each job. Use rubber gloves / gauntlets only when − line voltage is 5 kV or lower; − carrying out earthing; − opening AB switches; − using portable telephones; and − working on street light fittings. Maintain minimum distances as follows while working: LT 0.9 m (3 feet) 11 kV 2.5 m (8 feet 6 inches) 33 kV 2.7 m (9 feet) 66 kV 3.0 m (10 feet) 132 kV 3.5 m (11 feet) 220 kV 4 m (14 feet) While earthing 3.5 to 4.5 m (12 to 15 feet) Use safety belts while working on poles / platforms above 3 m height and learn the − proper way of using and removing the belt; and − proper way to get up or get down the pole and also the way to change direction. Always use insulated pliers and screw drivers (and only on LT). 55 Electrical Safety and Treat all electrical conductors and apparatus always as live and Disaster Management consequently dangerous to human life unless it is positively known to be dead and properly earthed and take precautions accordingly. Keep safe distance from rotating equipment. Do not attempt to handle them while working. While working on live conductors, do not roll-up sleeves as dry cloth gives some protection against shocks. When more than one Low Tension (LT) circuit is laid from a transformer, ensure that street light circuits are also separate. It is better to take line clear on both Current Transformer (CT) circuits. When loads on one transformer are transferred on to another, note it in the log book and intimate the duty staff. Ensure all three blades of AB Switches are open before working. Remember that loose connections can cause fires. Maintain discipline and the right attitude. Avoid haste while working. Avoid joking while working. Mind your personal safety and do not depend on others. DON’Ts Do not wear loose dresses or dresses having metal buttons. Do not use shoes with metal nails etc. Shoes should preferably have rubber soles. Do not use items made of metal like chains of wrist watch, key bunches, rings, bracelets, etc. while on work as these might come in close proximity to live parts and cause serious, if not fatal, injury. Do not throw tools at each other while at work. Do not work if you feel exhausted. Do not use rubber gloves / gauntlets should not be used for works of voltage class 33 kV and above. + , - Electric shock and fire are two major hazards in electrical installations and we would like to deal with them in some detail. We begin by taking up the 56 prevention and handling of electric shock. 7.4.1 Prevention and Handling of Electric Shock Accident Prevention and You have learnt in Unit 6 that electricity always attempts to travel to the Protection ground and will follow the path of least resistance to get there. If a conductor of electricity becomes available, electric current will follow that path to ground. The tools and equipment you use and even your own body, which is Electricity travels at approximately 70% water, are excellent conductors. Becoming part of the path very high speeds, at to ground can damage your equipment and can cause serious personal injury which you don't get including severe burns and even death (Box 7.3). a warning. There is no time to react. This is why it is important Box 7.3: Some Facts about Electric Shock to RESPECT ELECTRICITY each People suffer from electric shock when they touch an electrically charged and every time you object while in contact with another surface capable of conducting electricity use it or work to the ground. The current then flows through them. The severity of the around it. shock depends on the amperage, duration of contact and resistance of the All voltages are pathway through the body. For example, damp skin is less resistant to dangerous. Even low current flow and permits greater current to flow through. For this reason, you voltage shock may should work in a dry environment while handling electrical equipment. be fatal. The seriousness of a shock also depends on the path the current takes through the body. For example, a small current passing through the heart is much more critical than current passing between two fingers of the same hand. Testing for live current with one hand instead of two reduces the risk of a dangerous shock by making current less likely to flow through the heart. In a serious shock accident, the path that the electric current takes through the body gets very hot. Burns occur all along that path, including the places on the skin where the current enters and leaves the body. People can feel electrical currents at levels as low as approximately 1 milliampere (mA) current, which produces a slight tingling sensation. Increasing current levels above the 5 mA "let go" threshold can cause loss of muscular control, irregular heart rhythm and, finally, cardiac arrest. Five mA is only a small fraction of the current needed to power a 60-watt bulb, which draws about 1/2 amp, or 500 mA. Electrocutions can occur even if actual contact is not made with the line. The greater the line voltage, the farther electricity is able to "jump" to a ground conductor. Personnel working in power utilities can safeguard themselves by following the practices described in this section. In Table 7.2, we outline the measures that can be taken to prevent and handle electric shock. Technicians who work on electrical installations and equipment can prevent accidents by following these general instructions. 57 Electrical Safety and Table 7.2: Preventing and Handling Electric shock Disaster Management DOs DON’Ts Place yourself in a safe and Do not rely for protection secure position to avoid upon the care assumed to be slipping, stumbling, or moving exercised by others. backward against live conductors or apparatus. Stop all out-doors work on Do not take unnecessary risk electrical system in the event of with electricity. Low voltage, near approach of a lighting under certain circumstances, storm. can be more dangerous than high voltage. Disconnect the supply Do not leave the casualty in immediately in case of fire near contact with live apparatus. electrical apparatus. SWITCH OFF CURRENT IMMEDIATELY. Remove the casualty from the Do not discontinue artificial cause, render first-aid and respiration until recovery or send for doctor and take the death is certified by doctor. casualty to a hospital or It may take even more than dispensary. 2 to 3 hours for recovery. Study carefully and practice Do not attempt to disengage first-aid treatment for injured a person in contact with a persons such as the live apparatus which cannot instructions for resuscitation be switched OFF (artificial respiration) after immediately. Insulate electric shock, displayed at yourself from earth by every major electrical standing on rubber-mat or installation. dry-board before attempting to get him/her clear. Do not touch his/her body. Pull him/her by clothes if they are dry or push him/her clear with a piece of dry wood. Report all accidents, whether Do not remove the body minor or major, non-fatal or without the permission of fatal, immediately to the the Police even after person in-charge. certification of death by doctor. 58 Some additional precautions are given below: Accident Prevention and persons other than utility employees should not try to replace street lights Protection or set right service wires; the nearest utility office should be informed if loose or hanging wires are noticed; take extra precautions when working in abnormally damp areas; when, either accidentally or otherwise, live mains and apparatus constitute a danger to persons in a public place, a person should be detailed to stand-by and personally warn the public until the danger has been removed; all portable electrical apparatus should be regularly examined, tested and maintained to ensure that the apparatus and leads are in good order; all loose wiring, such as flexible cables for portable lamps, tools and trailing cables and other portable and transportable apparatus, should be inspected and tested regularly at frequent intervals to ensure safety; while drilling bore wells it should be ensured that the casing pipes do not touch live wires while they are being lifted up; unauthorized persons should not − go near the distribution transformers; − attempt replacement of transformer fuses; − touch low lying or snapped conductors; − lean against electric poles; and − stand beneath overhead lines while heavy winds are blowing. Precautions to be taken before providing Temporary Earth Ensure that the line / equipment are not live. Allow only authorized person to provide temporary earth or remove it. Firmly connect insulated wires (for providing earthing) to earth electrode before touching any equipment. Take care that the earth wire is not close to other live wires. Provide temporary earth on both sides of work spot. While disconnecting, first disconnect the earth rods from line / equipment. Ensure that the person providing the temporary earth wears rubber gloves/ gauntlets. Ensure that the person providing the earthing procedure is at a lower level than the line / equipment being earthed and other workmen are 6 metres away while earthing. 59 Electrical Safety and Do not allow the earthing to be disconnected until the whole work is Disaster Management completed and cleared of people and materials. Make sure that while work is being done on a 3 phase line, all conductors are earthed even if work is being done only on one phase. Ensure that while one or more workmen are working at a height, others are away so that if tools or materials are dropped accidentally, they are not hurt. Every employee should watch his/her counterparts that safety procedures are being followed. Whenever a switch is found open, check up why it is kept open, examine the parts of lines and equipment it is controlling and ensure that it is safe to recluse before doing so. Ensure that your hands or clothes are not wet while earthing / working. It is unsafe to check whether a line is live or dead with bare hands or other methods.. )%( !" ! / " % 0 1 Recall an accident due to electric shock at your work place. How was the case handled? What more could have been done? How could the accident have been prevented using the measures described in this section? ……………………………………………………………………………………… ………………………………………………………………………………………. 7.4.2 Line Clears and Precautions In the course of your work, you would be supervising technical personnel working on various electric lines. Therefore, you should be aware of the associated precautions. We begin with safety around overhead lines. Safety around Overhead Lines Overhead power lines are not insulated and looks can be deceiving. What may appear as insulation is weatherproofing material. Wires should not be touched under ANY circumstances. There is a minimum safe distance which should be maintained when working near energized power lines and you have read about it in the previous section. Note that the minimum safe distance increases as the voltage increases. Safe distances also can be affected by weather conditions and other factors. Additional minimum safe distances for various voltages are shown in Table 7.3. 60  Table 7.3: Minimum Safe Distances around Overhead Power Lines Accident Prevention and Protection Line voltage Minimum safe distance Up to 50 kV 3 m (10 feet) 50k to 200 kV 5 m (15 feet) 200to 350 kV 7 m (20 feet) 350to 500 kV 8 m (25 feet) 500 to 750 kV 12 m (35 feet) 750 to 1,000 kV 15 m (45 feet) We now describe the other safety precautions that need to be observed. Till a Line Clear (LC) is received from all sources every line or equipment should be treated as live. No person should get up a pole or work on any lines or equipment unless s/he is specifically authorized to do so. Line clears can be issued or received only by authorized persons. When it is not possible to receive or return line clear in person, the same can be done over telephone but clear identity by way of voice and also a code should be followed. Adequate clearance between lines on which work is being done and other live wires should be ensured or line clears taken on those lines also. While issuing line clear − switch off supply and ensure that the work spot where LC is requisitioned is disconnected from all possible sources of supply; − ensure personally that all blades of all operating switches are open; and − discharge the line / equipment using properly earthed discharge rods and by wearing rubber gloves / gauntlets. While returning line clear − only the person who obtained the line clear can return the same; − the person returning the line clear should ensure that the line / equipment is clear of all people, materials and earthing; − inform all colleagues that the LC is being returned and that it is no more safe to work on that line/equipment; − person receiving back the LC should ensure that no more LCs are pending return; and 61 Electrical Safety and − the entire team of personnel should stay back until such time as the Disaster Management line/equipment is recharged and leave the work spot only after re- charging. You may like to go through the following check list before you permit your technicians to work on electric lines. CHECKLIST BEFORE WORKING ON ELECTRIC LINES Have you undergone safety training? Have you opened the A B Switch feeding supply? Are the LT fuses removed? Are cables at Dn box away and not touching it? Have you provided temporary earths at work spot? Are you wearing gloves? Did you check the earth rod in place? Are you wearing helmet? Have you taken the safety belt with you? Are you confident of getting up the pole? Did you ensure that all other members in your team are following all safety precautions? An LC Form (see format in Appendix 2) needs to be filled up and signed by an authorized person. 7.4.3 Fire Prevention and Protection Fire can be a major safety hazard in electrical installations and you must know the safety procedures in case of a fire breaking out or to prevent fire. Every substation should train its employees in fire fighting. It should form its own fire fighting team. Teams should be given frequent mock drills. The duty of each member of the fire fighting team should be written and circulated among the staff. A list of all employees with their contact numbers and home addresses should be displayed in the substation. 62 Fig. 7.11: Fire − a Major Hazard in Electrical Utilities First and foremost, you should be aware of the factors that feed fire so that Accident you can prevent it by eliminating them. This is the basic principle of fire- Prevention and Protection fighting. Then, you should know certain general guidelines for preventing fire in your workplace, which should be followed at the organisational level. PRINCIPLE OF FIRE-FIGHTING Eliminate one of the three factors that cause fire: HEAT: By cooling water, etc. OXYGEN: By smothering and excluding air. FUEL: By segregation, cooling or smothering. REMEMBER: JUST BREAK THE FIRE TRIANGLE! PREVENT FIRE! Box 7.4: General Guidelines for Preventing Fire Eliminate potential sources of fire. Select adequately rated equipments for normal and abnormal duties. Install, operate and maintain the equipment within the limit of design. Prevent Hot Spots: Overloading should not be done as it causes insulation failure and fire. Heat detector alarm system and protective relay should be used to alert and disconnect equipment before preset temperature is reached due to overload. Adopt arrangements necessary to limit the spread of fire as well as its control. All oil filled equipment such as transformers and switchgears should be located outdoors. Indoor transformers and switchgears should be dry type. In a substation, switchgears and transformers should be kept in separate areas. Auxiliary room, Battery room and Control room should be separate and located away from main power equipments. Two exits should be provided in the rooms where operating personnel work. It is a statutory requirement that the company’s and consumers’ switch gears should be separated by fire proof wall. 63 Electrical Safety and Preventing Fire and Explosions at the Individual Level Disaster Management Here are some Dos and Don’ts, which will help you to prevent fire breaking out or spreading in an electrical installation. Pay special attention to these instructions as fire can be devastating. DOs Organize precautionary fire-drill and check fire-fighting apparatus periodically. Have sufficient number of fire extinguishers located in strategic positions, so that they may be available for immediate use in various areas. Wipe up oil as soon as possible; use sand to cover oil spots. Keep flammable material only in special containers and fire-proof rooms. Keep flammable liquids in approved safety cans and identify them by proper labels. Varnish, paints, lacquers and thinners are highly inflammable and should be stored away from all open flames or possible sources of ignition. Matches and open flames should not be used where varnish paint or lacquer is being applied with a spray gun. Disconnect the supply immediately in case of fire near an electrical apparatus. Make sure, when using water hose that the jet of water does not come into contact with live apparatus. Be sure that the personnel are familiar with the location and proper use of fire extinguishers in their work area. DON’Ts Do not allow waste paper, rags and other combustible material to accumulate. Do not allow open flames and smoking in all such areas where inflammable liquids or gases are stored or being used. Such areas should be posted with appropriate warning signs. No employee should smoke or use matches or open flames on customer’s premises unless it is positively known that such action does not conflict with the customer’s rules. Do not use fire extinguishers or electrical equipment unless they are clearly marked as suitable for that purpose. Use sand blanket instead. Do not throw water on live electrical equipment. It is dangerous to you. You may need to use fire extinguishers when fire breaks out. In order to be able to use various classes of fire extinguishers, you should know about different types of fire that is categorised according to the materials that are on 64 fire.  Accident TYPES OF FIRE Prevention and Protection 1. Class A – Wood, paper, cloth, trash, plastics, solid combustible materials that are not metals 2. Class B – Flammable liquids such as gasoline, oil, grease, acetone, any non-metal in a liquid state 3. Class C – Flammable gases such as propane, butane, acetylene 4. Class D – Metals like potassium, sodium, aluminium, magnesium You may like to know: What should you do if fire breaks out in spite of all precautions? HOW TO USE A FIRE EXTINGUISHER Simply remember: P-A-S-S P – PULL THE PIN Pull the Pin at the top of the extinguisher A – AIM THE NOZZLE LOW Aim the nozzle or the outlet towards the base of the fire and then release the hose and point. Some hose assemblies are clipped to the body of the extinguisher. Fig. 7.12: Different Types of Fire S – SQUEEZE THE HANDLE, LEVER Extinguishers Squeeze the handle, lever to release the extinguishing agent. In some cases valves are present. Before approaching the fire try a short burst. S – SWEEP We will try and show you a video film on Sweep from side to side at the base of the how to use fire fire until it is out. After fire is out watch for extinguishers in one of our video- the smouldering hot spots and possible re- conferencing flash. Put off the fire completely. sessions. 65  Electrical Safety and Extinguishing Fires Disaster Management Fire buckets, extinguishers and emulsifiers are the means of fighting fire in power electrical installations. Fire Buckets are of 9litres capacity and filled with sand. These are painted white from inside and post office red colour from outside with “FIRE” written on it. Some fire extinguishers are shown in Fig. 7.12. If you wish to learn some more details of fire-fighting in electrical installations, you may read Appendix 3. Of course, you and your workforce should know how to use fire extinguishers. Before studying further, you may like to recapitulate what you have learnt in this section. 2 % %( !" ! List the steps you would take for preventing fire..……………………………………………………………………………………… ……………………………………………………………………………………….. First Aid means what you should do to reduce the suffering of the patient after an accident until the doctor arrives. It is very important that you be TRAINED in administering first aid as it may give life to a dying person. The first and foremost rule is to BE PREPARED. In fact, the rule is very clear in this respect. INSPECTION OF FIRST AID EQUIPMENT AND BOX All first aid equipment and box in grid station, substations and vans should be checked periodically by an authorized person who will sign the format F08 (COR – P-12) placed therein together with the date on which the check was carried out. 7.5.1 First Aid Instructions You must take the following steps immediately in the event of injury due to an accident: Fig. 7.13: Contents of the Remove the patient from the source of accident / remove the cause of First Aid Box; injury. (Source: www.safetyquest Keep the injured person lying down in a comfortable position. online.com) If the breathing has ceased, take artificial respiration measures immediately to restore it (see Sec. 7.5.2). 66  Accident If the patient has received burns, attend to them as explained below. Prevention and When the patient has fractured a bone, do not attempt to move him/her. Protection Send for medical help. Treat the patient for shock. Keep the patient warm. Never give water to patient. Keep away from the patient as per prescribed standard distances. We now spell out the first aid measures for victims of electric shock, fire and other injuries in the boxes given below. Box 7.5: First Aid Treatment for Electric Shock RELEASE FROM CONTACT Switch off the electric supply immediately or send someone to do so. Do not attempt to remove a person from contact with high voltages unless suitable articles insulated for the system voltages are used for the purposes. When attempting to free a person from contact with low or medium voltage, use rubber gloves, shoes, mat, cardboard, plastic, wood or insulated stick, but if these are not available use a loop of rope, cap or coat to drag the person free. WHATEVER IS USED SHOULD BE DRY AND NON-CONDUCTING. AFTER RELEASE As soon as the victim is clear off the conductor, check the person's breathing and pulse. Rapidly feel with your finger in his/her mouth and throat and remove any foreign matter (tobacco, false teeth etc.). If either pulse or breathing has stopped or seems dangerously slow or shallow, begin artificial respiration immediately. Do not stop to loosen the victim’s clothing now; every moment of delay is serious. Keep the patient warm. If the person is faint or pale or shows other signs of shock, lay the person down with the head slightly lower than the trunk of his or her body and the legs elevated. Treat any major burns as per instructions in Box 7.6. PHYSICAL SHOCK In addition to suffering from electric shock it is also probable that the patient is suffering from physical shock, and it is important that this condition also be treated simultaneously. Keep the patient warm with blankets or coats, and if available, apply hot water bottles on the feet. 67 Electrical Safety and Box 7.6: Burns Disaster Management BURNS First distinguish a MINOR BURN from a SERIOUS BURN. These three classifications will help you determine emergency care: First-degree: The least serious burns are those in which only the outer layer of skin (epidermis) is burned. Treat this as a minor burn unless it involves substantial portions of the hands, feet, face, groin or buttocks or a major joint. Second-degree: When the first layer of skin has been burned through and the second layer of skin (dermis) also is burned, the injury is termed second-degree burn. Blisters develop and the skin takes on an intensely reddened, splotchy appearance. Second-degree burns produce severe pain and swelling. If the second-degree burn is no larger than 2 to 3 inches in diameter, treat it as a minor burn. If the burnt area is larger or if the burn is on the hands, feet, face, groin or buttocks or over a major joint, GET MEDICAL HELP IMMEDIATELY. Third-degree: The most serious burns are painless and involve all layers of the skin. Fat, muscle and even bone may be affected. Areas may be charred black or appear dry and white. Difficulty inhaling and exhaling, carbon monoxide poisoning or other toxic effects may occur if smoke inhalation accompanies the burn. For minor burns, including second-degree burns limited to an area no larger than 2 to 3 inches in diameter, take the following action: Cool the burn. Hold the burned area under cold running water for 15 minutes or immerse it in cold water or cool it with cold compresses. DON'T PUT ICE ON THE BURN. Once a burn is completely cooled, apply an aloe vera lotion, a triple antibiotic ointment or a moisturizer. Cover the burn with a sterile gauze bandage. Don't use fluffy cotton, which may irritate the skin. Wrap the gauze loosely to avoid putting pressure on burned skin. Give an over-the- counter pain reliever. CAUTION: DO NOT USE ICE. PUTTING ICE DIRECTLY ON A BURN CAN CAUSE FROSTBITE, FURTHER DAMAGING YOUR SKIN. For major burns, call for emergency medical assistance. Until an emergency unit arrives, follow these steps: DO NOT REMOVE BURNT CLOTHING. However, do make sure the victim is no longer in contact with smouldering materials or exposed to smoke or heat. Make sure that the victim is breathing. If breathing has stopped or you suspect that the person's airway is blocked, try to clear the airway and, if necessary, carry out artificial respiration. COVER THE AREA OF THE BURN. Use a cool, moist sterile bandage or clean cloth. 68  Box 7.7: Heat Stroke and Heat Exhaustion Accident Prevention and Protection HEAT STROKE Hot and humid atmosphere and inadequate intake of water can lead to a heat stroke. It is a serious and often fatal condition. Heat stroke is an entirely different reaction in the human body, to the same conditions, which give rise to heat exhaustion. The victim shows mental excitement, restlessness, vomiting, muscular cramps and high temperature. CARE AND TREATMENT Wrap the patient up completely in cold water soaked bed sheet. Fan vigorously. Send for doctor. HEAT EXHAUSTION Heat exhaustion occurs among workers in stuffy atmosphere or in overheated, poorly ventilated rooms. The person may feel giddy or faint. The skin of the victim is always cold and moisture retention by wearing loose clothing, drinking large quantities of water is possible. ACTIVE FIRST AID TREATMENT FOR HEAT EXHAUSTION Remove patient to cooler conditions in the fresh air. Lay him/her down and loosen all clothing around neck. Fan him/her vigorously. Dash cold water on the neck and head to stimulate the victim. There are scientifically approved methods to resurrect a person who has met with an electrical accident and we indicate some of them in this section. 69 Electrical Safety and THIS IS ONLY FOR INFORMATION AND AWARENESS. PLEASE DO NOT Disaster Management TRY THESE TECHNIQUES UNLESS YOU ARE TRAINED IN THEM. 7.5.2 Artificial Respiration and Chest Compression Artificial respiration involves a combination of mouth-to-mouth rescue breathing and chest compression (Fig.7.14). It keeps oxygenated blood flowing to the brain and other vital organs until appropriate medical treatment can restore a normal heart rhythm. Breathing: Mouth-to-mouth rescue breathing is the quickest way to get oxygen into a person' s lungs. However, if you are not trained in emergency procedures, doctors recommend skipping mouth-to-mouth rescue breathing and proceeding directly to chest compression. The reason is that if you are distracted by trying to perform unfamiliar breathing techniques, valuable lifesaving minutes might be lost for the person who needs help. The most important thing you can do is to proceed directly to chest compression to move blood to vital organs, particularly the brain and heart. If you are trained in emergency procedures, it is important to do both mouth-to-mouth rescue breathing and chest compression. Chest compression: Chest compressions replace the heartbeat when it has stopped. Compressions help maintain some blood flow to the brain, lungs and heart. You must perform rescue breathing anytime you perform chest compressions. Before starting artificial respiration, assess the situation: Is the person conscious or unconscious? If the person appears unconscious, tap or shake his or her shoulder and ask loudly, "Are you OK?" If the person doesn't respond, follow the steps below and get help by calling for emergency medical assistance. If you cannot leave the scene, have someone else call. To perform mouth-to-mouth rescue breathing and chest compression: Position the person so you can check for signs of life by laying the person flat on their back on a firm surface and extending the neck. Open the person' s mouth and airway by lifting the chin forward. Determine whether the person is breathing by simultaneously listening for breathing sounds, feeling for air motion on your cheek and ear, and looking for chest motion. If the person is not breathing, pinch his or her nostrils closed, make a seal around the mouth and breathe into his or her mouth twice. Give one breath every five seconds — 12 breaths each minute — and completely refill your lungs after each breath. 70  Accident Prevention and Protection (a) (d) (b) (e) (c) Fig. 7.14: Artificial Respiration in Basic Life Support. a) The Victim should be Flat on His/Her Back and His/Her Mouth should be Checked for Debris; b) If the Victim is Unconscious, Open Airway, Lift Neck, and Tilt Head Back; c) If Victim is not Breathing, begin Artificial Breathing with Four Quick Full Breaths; d) Check for Carotid Pulse; e) If Pulse is Absent, Begin Artificial Circulation by Depressing Sternum (Source: www.surgeryencyclopedia.com) If there are no signs of life — no response, movement or breathing — begin chest compressions (Fig. 7.15): Place your hands over the lower part of the breastbone, keep your elbows straight and position your shoulders directly above your hands to make the best use of your weight. Push down 1 ½ to 2 inches at a rate of 80 to 100 times a minute. The Fig. 7.15: Chest pushing down and letting up phase of each cycle should be equal in Compression duration. Do not jab down and relax. After 15 compressions, breathe into the person's mouth twice. After every four cycles of 15 compressions and two breaths, recheck for signs of life. Continue the rescue manoeuvres as long as there are no signs of life. Continue the artificial respiration without interruption, until natural breathing is restored, or until the physician arrives. A brief return to natural respiration is not a certain indication for stopping the resuscitation. The patient must be 71 Electrical Safety and watched, and if natural breathing stops, artificial respiration be resumed at Disaster Management once. In carrying out resuscitation it may be necessary to change the operator. This change must be made without losing the rhythm of respiration. By this procedure no confusion results at the time of change of operator and a regular rhythm is kept up. If patient recovers before the medical assistance arrives, regulate your artificial respiration to the rate of the patient’s breathing, and when s/he has sufficiently recovered make her/him comfortable and give hot tea. Do not allow patient to exert even by walking until a doctor has seen her/him as the shock may have affected his heart. On this note, we would like to end the unit and summarise what you have studied. 2 3 In this unit, we have dealt with various aspects of accident prevention, handling and protection. We have presented general information about direct and indirect causes of accidents, accident reporting procedures and investigation and the costs of accidents. We have discussed various general measures that can be taken to prevent accidents including good housekeeping and training of personnel for upgrading their skills and maintaining the correct attitude towards accidents. We have focused on cases of electric shock and fire. The safety precautions and simple methods for handling such cases have been presented. We have also discussed some preliminary first aid measures for cases of electric shock, burns and other physical injuries. We have presented some elementary techniques of providing artificial respiration to revive accident victims. 1. Discuss the causes of accidents in power utilities. 2. What accident reporting and investigation procedures are followed in your utility? 3. Suppose an accident occurs in your utility due to any of the following factors: a) Snapping of conductors b) Accidental contact with live electric wire / equipment 72  c) Violation / neglect of safety measures / lack of supervision Accident d) Defective appliances / apparatus / tools Prevention and Protection e) Inadequate / lack of maintenance f) Unauthorized work How will you manage the situation after an accident has occurred? 4. Discuss the measures that should be taken for preventing and handling cases of electric shock. 5. Explain the major causes for fire outbreaks in a power utility. What techniques can be used for handling and preventing such fires? 6. Describe the first aid measures to help the victims of a) electric shock, b) burns, c) physical shock, d) heat exhaustion, and e) heat stroke. 73 Electrical Safety and Disaster Management )) 4 ) 1. Date and time of Accident. 2. Place of accident.( Village/Town, Tehsil/Thana, District and State). 3. System and voltage of supply. (Whether EHV/HV/LV Line, sub-station/ generating station/ consumer’s installations/ service lines/ other installations). 4. Designation of officer in charge of the supplier in whose jurisdiction the accident occurred. 5. Name of owner / user of energy in whose premises the accident occurred. 6. Details of victim(s): a) Human: Sl. Name Father’s Sex of Full Postal Approximate Fatal / No. Name Victim Address Age Non fatal 1 2 3 4 5 6 7 b) Animal: Sl. Description of Numbers Name(s) of Address(es) of Fatal / No. Animal(s) Owner(s) Owner(s) Non-fatal 1 2 3 4 5 6 7. In case the victim(s) is / are employee(s) of supplier a) Designation of such person(s). b) Brief description of job undertaken if any. c) Whether such person / persons was / were allowed to work on the job. 8. In case the victim(s) is an employee(s) of a licensed contractor:- a) did the victim(s) possess any electric workmen’s permit(s), supervisor’s certificate of competency issued under Rule 45? If yes, give number and date of issue and the name of issuing authority. b) name and designation of the person who assigned the duties of the victim(s). 74 9. In case of accident in the supplier’s system, was the permit to work (PTW) taken? Accident Prevention and 10. a) Describe fully the nature and extent of injuries, e.g. fatal / disablement Protection (permanent or temporary) of any portion of the body or burns or other injuries. b) In case of fatal accident, was the post-mortem performed? 11. Detailed causes leading to the accident. (to be given in a separate sheet annexed to this form) 12. Action taken regarding first-aid, medical attendance, etc. immediately after the occurrence of the accident (give details). 13. Whether the District Magistrate and Police Station concerned have been notified of the accident (if so, give details). 14. Steps taken to preserve the evidence in connection with the accident to extent possible. 15. Name and designation(s) of the person(s) assisting, supervising the person(s) killed or injured. 16. What safety equipments were given to and used by the person(s) who met with this accident (e.g. rubber gloves, rubber mats, safety belts and ladders etc). 17. Whether isolating switches and other sectionalizing devices were employed to deaden the sections for working on the same? Whether working section was earthed at the site of work? 18. Whether the work on live lines was undertaken by authorized person(s). If so, the name and the designation of such person(s) may be given. 19. Whether artificial resuscitation treatment was given to the person(s) who met with the electric accident? If yes, how long was it continued before its abandonment? 20. Names and designations of persons present at and witnessed the accident. 21. Any other information / remarks. Signature Place: Name……………….. Time: Designation………… Date: Address of the person reporting 75 Electrical Safety and Disaster Management )) 4 1. I hereby declare that the following line / equipment is made dead and that it is cleared from all possible sources of supply. 2. I have switched off all points of supply under my control which can energize the line / equipment 3. I have fixed “MEN ON LINE Boards” indicating that line clear is issued at all such points. 4. Please obtain similar LC from other sources if the line / equipment can be charged from alternate sources other than mine “Line / equipment on which LC is issued” 5. All other parts are live and dangerous. Discharging rods are connected at the following points at the source side 1 2 6. Please ensure that the temporary earths is provided on either side of the workspot before proceeding with the work 7. Name, designation, date & time of issue Sd/ ……….. 8. Received the above line clear Name, designation, date and time Sd/…………. 9. Return of line clear I hereby declare that the above line / equipment is cleared of all men, materials and temporary earths and that I have alerted all men that it is no more safe to work on the live / equipment Sd/- Name, designation, date & time 10. All earths / discharge rods removed at source end, men online boards removed, ensured no more line clears are pending hence LC is cancelled Sd/- Name, designation, date & time 11. Line / equipment recharged on (date) at Hrs… mts.. Sd/- Name, designation, date & time 76  )) 4$ ) * Accident Prevention and ) Protection 5 Electricity is a clean form of energy, which can be transported from the source of supply to the place of usage. This inherent property of electricity is advantageous in minimizing the risk of fire. It has been accepted at large-scale This material has even in potentially hazardous areas. Measures adopted for reliable operation been adapted from invariably reduce the risk of fire. Therefore all possible precautions should be the Article by taken at the time of design. Shri Jagmohan Vaid of Unique Elimination of Electric Fire Hazards Complete Safety Solution presented Electrical faults caused by failure of insulation, improper earthing or any other in the DRUM materials. snag in the system can ignite fire. The design approach should eliminate/ minimize these causes. Insulation damage is caused by thermal stress, mechanical stress, moisture, dirt, and high voltage. The following measures would help in tackling insulation damage: To avoid thermal stress, we should choose equipment of suitable rating for expected duty. To minimize mechanical vibrations, equipment should be installed on properly designed foundation. Idle equipment in humid areas should be kept warm by use of heaters. Lightning arrestors should be installed to prevent high voltage search. To ensure the system is maintained within the desired limit of operation, automatic voltage regulators should be used. Over voltage relays are used to isolate the equipment, which are subjected to excessive voltage than permitted. Guards are provided on transmission lines to prevent fault due to birds. Vermin proof enclosures should be used for indoor switchgears. Insulation failure results in dissipation of large magnitudes of fault current at the place of fault. Therefore effective steps should be taken to limit the magnitude of fault currents as well as its duration. Reactors should be used in the power system network at places where fault levels are to be restricted. Protective relays, circuit breakers and adequately rated fuses should be used to minimize fire during fault. Protective relays provide the first line of defence. These relays are backed up by “Back Up” relays. Reliability measures are built in to ensure correct operation when required. Grounding The ohmic value of the grounding main of electrical installation should be as low as possible. It is necessary to connect all ground points in the area grid by duplicate earth connections. Segregated non-current carrying metallic parts should be electrically bonded. Since improper grounding may give rise to 77 Electrical Safety and voltage surges, which cause fire, it is necessary to keep a record of the Disaster Management ground resistance value as well as the physical condition of the grounding mail. Maintenance Operating Procedures Besides following the routine maintenance practices prescribed for the equipment, special diagnostic tests should be connected to detect incipient faults. High voltage testers, timing test, contact and insulation resistance measurements are some tests, which could be carried out. Monitoring the trend of the results of tests will enable you to take out equipment and rectify the faults before they develop into serious troubles. In polluted areas, the insulators require frequent cleanings. Silicon grease is applied to insulators to reduce pollution deposits. Operating instructions should be written taking into account all anticipated normal and abnormal operating conditions. The safety tagging system should be adopted. Interlocks must form part of the equipment designed to ensure that electrical equipment is put in and taken out in the correct manner. Arrangements to Limit Spread of Fire Switch Gears: Switchgear cubicles should be