In the previous section, we have studied the various method of artificial respiration,which are based upon the elementary first aid and to be provided to a electric shock victim, who is feeling some problem in natural breathing or the person is in fainted position. Now the question arises, can we prevent such type of mishaps or accidents? The answer will be definitely “Yes we can”. It could be possible, only if we strictly follow the safety precautions or safety rules, framed for the safen operation and maintenance of the plant or machines etc. So, Indian Electricity (I.E.Rule) rules have been framed, matching with the International standards for the safe operation and use of electricity in our daily life.
The most important tool in safety precaution is the earthing. We know that earth wire resistance should be as low as possible, which may be 0.2 ohms. All the metallic parts of machine and equipment are connected with earth wire and kept at ground potential. Due to this low resistance path for the leakage current between the body of the machine or equipment and ground, there will be a flow of heavy short-circuit current. This short-circuit current completes its circuit through the earth and the person working on the machine will remain safe as it has high resistance as compared to earth wire. Simultaneously the M.C.B. may be trippedor the fuse wire may be blown due to flow of heavy current and supply to the equipment will be switched off.
So, all the alternators, equipment, machine, and every third pole and the neutral wire of the transformer are earthed. Human body is a good conductor of electricity.When live wire touches the body, current completes its circuit through body and earth. Muscular functions of the body are paralysed due to the current’s action on the nervous system. The heart and the respiratory organs which may cease to function, causing breathing to stop serious burns and resulting in death. So, we should be careful while working on live system or handling the electrical appliance and equipment.
The portable equipment are connected with one earth wire whereas the heavy machines and equipments are connected with at least two earth wires. Some-times, one earth wire is disconnected or its resistance is increased in dry or summer season the overall resistance will remain within safe limit i.e. less than 0.2 ohms.
Suppose the overall resistance is increased than the safe limit, we have to reduce it with in permissible limit by adding some normal drinking water.While working on pole for some minor repair we should be equipped with insulated safety belt and ladder should be hold by another person so that it may not slip. If we have to work on live conductors or there is some break down in the distribution line, we should never try to complete the job without proper permission to work.So, it will be better to apply for permit to work (PTW) from the sub-station authority. Ensure that the Oil Circuit Breakers (O.C.B) and isolators are switched off properly and warning plate to this effect has been hanged on the oil circuit breaker and isolator handle that “Man At Work and Do Not Operate”. After getting permission to work, short-circuit all the three phases, neutral wire and earth to the ground on both the sides of the pole, with the help of specially prepared wire for the purpose. Suppose by mistake either the oil circuit breaker (OCB) or isolator is switched on. All conductors are already at almost ground potential, which acts as short circuit and heavy current will flow to the ground. This heavy current will trip the oil circuit breaker and the supply to the line is switched off. The person working on the line will be safe.
Special care should be taken while using, handling and repairing the portable equipment or appliances, such as Heater, Table fan, Iron, Microwave oven and hair dryers etc. First we should ensure that these appliances are connected with the earth wire properly. While handling these, be ensuring the supply lead has been removed from the socket, because there may be a chance that neutral line is controlled through the switch. Under such circumstances, simply switching off the supply is not enough. There may be leakage of current from the insulation of the connecting wire and also from the winding of the motor. This type of accidents can be avoided by controlling the phase wire through the switch. The person working on the equipment should be well insulated from the ground or walls so that the current circuit could not be completed through the human body. If the appliances are properly earthed the fuse wire will be blown in case leakage of current. Some time it has been observed that the fuse does not blown-out, if it is overrating fuse wire. Under such circumstances connecting wires to the faulty appliances may be over heated and may catch fire. So, we should switch off the supply immediately and throw sand or dust, instead of throwing water on the electric fire. The best way is to use carbon-Dioxide fire extinguisher to over-come electric the fire.
Finally, we know the general attitude of the people. They tie steel wire with the pole/tower or stay wire, and use to dry the wet cloths or to hang them. Secondly,some-times it has been observed that people may use the same to tie their pet animals, especially in thickly populated areas. A warning plate should be fixed with pole, showing the skeleton of human and the operating voltage.
The most important tool in safety precaution is the earthing. We know that earth wire resistance should be as low as possible, which may be 0.2 ohms. All the metallic parts of machine and equipment are connected with earth wire and kept at ground potential. Due to this low resistance path for the leakage current between the body of the machine or equipment and ground, there will be a flow of heavy short-circuit current. This short-circuit current completes its circuit through the earth and the person working on the machine will remain safe as it has high resistance as compared to earth wire. Simultaneously the M.C.B. may be trippedor the fuse wire may be blown due to flow of heavy current and supply to the equipment will be switched off.
So, all the alternators, equipment, machine, and every third pole and the neutral wire of the transformer are earthed. Human body is a good conductor of electricity.When live wire touches the body, current completes its circuit through body and earth. Muscular functions of the body are paralysed due to the current’s action on the nervous system. The heart and the respiratory organs which may cease to function, causing breathing to stop serious burns and resulting in death. So, we should be careful while working on live system or handling the electrical appliance and equipment.
The portable equipment are connected with one earth wire whereas the heavy machines and equipments are connected with at least two earth wires. Some-times, one earth wire is disconnected or its resistance is increased in dry or summer season the overall resistance will remain within safe limit i.e. less than 0.2 ohms.
Suppose the overall resistance is increased than the safe limit, we have to reduce it with in permissible limit by adding some normal drinking water.While working on pole for some minor repair we should be equipped with insulated safety belt and ladder should be hold by another person so that it may not slip. If we have to work on live conductors or there is some break down in the distribution line, we should never try to complete the job without proper permission to work.So, it will be better to apply for permit to work (PTW) from the sub-station authority. Ensure that the Oil Circuit Breakers (O.C.B) and isolators are switched off properly and warning plate to this effect has been hanged on the oil circuit breaker and isolator handle that “Man At Work and Do Not Operate”. After getting permission to work, short-circuit all the three phases, neutral wire and earth to the ground on both the sides of the pole, with the help of specially prepared wire for the purpose. Suppose by mistake either the oil circuit breaker (OCB) or isolator is switched on. All conductors are already at almost ground potential, which acts as short circuit and heavy current will flow to the ground. This heavy current will trip the oil circuit breaker and the supply to the line is switched off. The person working on the line will be safe.
Special care should be taken while using, handling and repairing the portable equipment or appliances, such as Heater, Table fan, Iron, Microwave oven and hair dryers etc. First we should ensure that these appliances are connected with the earth wire properly. While handling these, be ensuring the supply lead has been removed from the socket, because there may be a chance that neutral line is controlled through the switch. Under such circumstances, simply switching off the supply is not enough. There may be leakage of current from the insulation of the connecting wire and also from the winding of the motor. This type of accidents can be avoided by controlling the phase wire through the switch. The person working on the equipment should be well insulated from the ground or walls so that the current circuit could not be completed through the human body. If the appliances are properly earthed the fuse wire will be blown in case leakage of current. Some time it has been observed that the fuse does not blown-out, if it is overrating fuse wire. Under such circumstances connecting wires to the faulty appliances may be over heated and may catch fire. So, we should switch off the supply immediately and throw sand or dust, instead of throwing water on the electric fire. The best way is to use carbon-Dioxide fire extinguisher to over-come electric the fire.
Finally, we know the general attitude of the people. They tie steel wire with the pole/tower or stay wire, and use to dry the wet cloths or to hang them. Secondly,some-times it has been observed that people may use the same to tie their pet animals, especially in thickly populated areas. A warning plate should be fixed with pole, showing the skeleton of human and the operating voltage.
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