ELECTRO SCIENCE CLUB BASIC ELECTRICAL SAFETY Sanjay Srivastava,TGT(WE)
One day Brity came to Tryti s home. He saw that Tryti was using metallic knife for repairing of electrical appliance. Bryti: Hi Tryti! Tryti: Hello! Bryti: What you are doing? Tryti: My Toaster is not working, just trying to repair. Bryti: Tryti, you are using metallic knife, cord is connected with socket and switch is ON. Tryti: Oh..Ohoooooooo And Do you know what happened to Tryti?. What is Electric Shock?. Why we get electric shock?. Electro Science Club- Class VIII Page 1
Reason of accidents:- Electricity is essential to modern life; it has become familiar part of our daily life. However, we tend to overlook the hazards electricity poses and fail to treat it with the respect it deserves. The Tryti got electric shock because he was not following the electrical safety rules.anyone can be exposed to the dangers of electricity hence everyone should be made aware of the dangers. Most electrical accidents occur because of Not using proper connecting devices for electrical equipments. Overloading on one electric supply outlet or extension board. Laying wires and / or electrical appliances in untidy way. Loose, overlapping or poorly insulated joints. Non availability of electrical safety equipments. Working on equipment without disconnecting from main electric supply. Using inappropriate or defective tools. Working without adequate training or appropriate equipment Inadequate precautions Misuse of electrical equipment. Can you define the following terms? Safety:-. Electrical Safety:-. Mention the safety rules overlooked by the Tryti. 1.. 2.. 3.. Electro Science Club- Class VIII Page 2
On the basis of shown pictures find how electrical hazard can take place. Write the reason:. Write the reason:. Write the reason:. Electro Science Club- Class VIII Page 3
Basic electrical safety To minimize the chance of electrical hazards following minimum steps should be taken to ensure electrical safety. Mains supplies Install new electrical systems as per Indian Electrical Standards. Use MCB and Isolator of appropriate rating for safety from overloading and short circuiting. Maintain all electrical installations in good working order Provide enough socket-outlets for equipment in use Avoid overloading socket-outlets using adaptors can cause fires Fix power cut off switch near fixed machinery to cut off power in an emergency Even portable equipment should beused with socket-outlets having switch,so that it can be easily disconnected in an emergency. Use Residual Current Devices (RCDs) or Ground Fault Circuit Interrupter for extra safety The RCD or GFCI provides additional safety. It is designed to shutoff electric power, if a ground fault is detected. The RCD or GFCI is useful near sinks and wet locations. However, they may not be useful for certain apparatus as they can cause equipment to shutdown unexpectedly. Though the RDC or GFCI is not guaranteed to stop an electrical shock, it is guaranteed to make the injury much less serious. The best place for an RCD is built into the main supply or the socket-outlet, as this means that the supply cables are permanently protected. RCDs for protecting people have a rated tripping current (sensitivity) of not more than 30 milliamps (ma). Remember: An RCD is a valuable safety device never bypass it If the RCD trips, it is a sign there is a fault. Check the system before using it again. If the RCD trips frequently and no fault can be found, consult the manufacturer of the RCD Use the RCD test button regularly to check that its mechanism is free and functioning. Use the right equipment Choose electrical equipment that is suitable for its working environment Ensure that equipment is safe when supplied and maintain it in a safe condition Electrical equipment used in flammable/explosive atmospheres should be designed not to produce sparks. Seek specialist advice when choosing this type of equipment. Protect light bulbs and other easily damaged equipment there is a risk of electric shock if they are broken. Maintenance and repairs Ensure equipment is fitted with the correctly rated fuse. Ensure cable ends always have their outer sheaths firmly clamped to stop wires working loose from plugs or inside equipment Replace damaged sections of cable completely never repair cuts with insulating tape. Use proper connectors to join lengths of cable don't use connector blocks covered in insulating tape or 'splice' wires by twisting them together Make sure all wires of plug are connected securely. Good practices: Formal visual inspection of plug, cable, cable-entry or input socket and the casing of the equipment are important before use. If any fault is identified, the item should be removed from use and repaired before being used again. All the electrical equipments should be switched off and unplugged after completion of work. Electro Science Club- Class VIII Page 4
Bryti wants details of electrical devices which reduces the risk of electrical hazard. You help him by collecting the picture of given electrical devices and write their use in term of electrical safety ELECRICAL DEVICE DIAGRAM USE ON/ OFF SWITCH KITKAT FUSE GLASS CARTAGE FUSE MINIATURE CIRCUIT BREAKER (M.C.B.) G.F.C.I. OR R.C.D. ELECTRICAL CUT-OUT Electro Science Club- Class VIII Page 5
How physical observation reduces the risk of electrical hazard?. What is overloading of Socket or extension board?. How over loading of socket increases the risk of electrical hazards?. How grounding reduces the risk of electrical hazard?. What do you understand by Fuse Rating?. Dangers from electricity The dangers associated with the electricity may be classified in following categories Injury from direct contact: Injury by shock. Injury from internal burns. Injury without current flow through body: Direct burns from electric arcs, spattered molten metal, etc. Radiation burns from very heavy arcs. Physical injury from false starting of machine, failure of crane controls, explosion of switchgear, etc. Injury from fire and explosion from electric ignition of flammable vapours, gases, liquids and solids Eye injury from electric arcs, Eye injury from current flow induced in or near the human body by intense electric magnetic fields: Injury from elevation of whole body temperature. Local injury such as cataract formation in the eye. Burns due to metallic objects such as rings, dental metal in close contact with local part of body. Electro Science Club- Class VIII Page 6
How shock occurs? Whenever electric current flows through our body and our body feely acute pain is known as electric shock. Electrical shock occurs either when an individual comes in contact with: both wires of an electric circuit, one wire of an energized circuit and the ground, a metallic part that accidentally becomes energized by contact with an electrical conductor Severity of the shock The severity and effects of an electrical shock depends on a numbers of factors, such as; The path of the current through the body The amount of current flowing through the body The length of the time of the exposure and Whether the skin is wet or dry. What to do in case of electrical shock? We are aware that the electricity will follow any available conductive path and it travels at the speed of light. The rescue of electrical shock victims depend on prompt action. In case of electrical shock, the following steps are to be taken immediately: Shut off the voltage at once. Do not make direct contact with any part of the victim s body with any part of your body. Try to free the victim from live conductor by using a dry piece of wood or dry plastic or wooden broom or dry clothing or other non conducting material. Determine the victim is breathing. If the victim is not breathing, apply cardiopulmonary rescue citation (CPR) and First- Aid without any delay In case of electrical shock, the following First Aid should be given to the victim: Cool the burn with running water. Cover the victim with a blanket. Do not attempt to remove burned clothing. Do not apply ice or any other ointment or cotton dressing to the burn. Handle the victim with care. Keep the victim from moving. Treat for shock. Maintain body temperature. Do not give anything by month. Call for emergency medical attention. Explain why Tryti got electric shock?. Write important steps you have to take to help the victim.. Electro Science Club- Class VIII Page 7
Dos for working with electricity: Always wear rubber soled shoes and safety gloves when working with electricity Use double insulated tools. Use rubber floor mating if possible Utilize nonconductive tools and ladders Use only THREE pin plugs, which provide a path to ground that helps prevent the built up or voltages that may result in an electrical shock or spark. Use shut off switches and / or circuit breakers to shut off equipment in the event of fire or electrocution Always use ground fault circuit interrupters around areas where there is water Keep combustible materials away from lamps or heating devices. Live parts of electrical equipments must be guarded against accidental contact Limit the use of extension cords or multiple adapters Inspect the wiring of equipment before each use Switch off lamps when changing light bulbs. Disconnect appliances before cleaning. Call the fire station in case of an electrical fire. Call the electricity office, if you see person has been electrocuted. Before you work on a rooftop television antenna, make sure the area is clear of power lines. Install antennas where they won t touch or fall on electric lines. If a cord or plug is warm or hot to touch, unplug it immediately, check wires, extension cords and appliances for signs of wearing. In case of an electrical fire, if you are safe, unplug the appliance and use DCP type fire extinguisher to douse the flames. Stay in the car during a storm because the rubber tires stop electricity from passing through it, if the car is struck by lightning or fallen cable. Don ts for working with electricity: Do not plug electrical appliances in bathroom unless specific safety devices have been installed. If you are in contact with water never touch electrical light switch. Do not put your fingers in a light bulb holder. Do not put any into an outlet except a plug. Do not leave electric devices where small children may have access. Do not use a lamp in a metal holder fixed to the end of a loose flexible wire as a portable hand lamp. Never climb transmission towers. Don t attempt to fix cord that have been cut or damaged. Never use damaged cords. Never pull out a plug by the cord. Never place electrical cords under carpets which can result in wearing of the cord. Never bend or remove the ground on a three pin plug, which is designed to help prevent shock and may save your life. Do not use extension cords as permanent wiring as they are not designed for it. Never use cords or plugs that show wear or damage, they can cause shock or fires. Do not overload an extension cord. Never puncture insulations of electrical cords by nailing them to any substances. While climbing trees stay away from those near power lines. ASSIGNMENTS (Submit one assignment online or offline on topics given below on or before 30/04/2016) 1. Electrical Safety Rules. 2. Electric Shock. 3. Electrical Fire 4. Safety Measures. 5. First Aid to victim of electric shock. 6. Factor affects the electric shock 7. Static electricity Hazard. 8. Artificial Respiration. Electro Science Club- Class VIII Page 8
TEST Electro Science Club- Class VIII Page 9
This is to certify that I (Name) (Roll Number) student of Class VIII, Section, completed this workbook in true spirit and enjoyed while completing the workbook. Date: Signature of Student This is to certify that my ward (Name) of Class VIII had completed the workbook Basic Electrical Safety in true manner. The information included in workbook seems useful for everyone. Date: Signature of Parent This is to certify that (Name) of Class VIII completed the workbook Basic Electrical Safety in true manner. He/ She has been awarded A / B/ C/ D/ E grade for effort. Date: Signature of Teacher Electro Science Club- Class VIII Page 10