Essay on Electric Shock and Its Treatment | Electrical Engineering

Here is an essay on ‘Electric Shock and Its Treatment’ for class 11 and 12. Find paragraphs, long and short essays on ‘Electric Shock and Its Treatment’ especially written for engineering and medical students.

Essay # 1. Causes of Electric Shock:

A person may even die due to electric shock. Death occurs in three ways:

(i) Heart may be rent and breathing is stopped;

(ii) The nerve keeping the respiratory system working may be blocked and breathing is stopped;

(iii) A part of the body may be severally burnt out.

Shock becomes most severe when heart is rent. A person is sure to die at this stage. But if the nature of shock is less severe as mentioned in (ii) & (iii) above, a person may be brought back to life by proper treatment.

The damage caused in a body due to electric shock depends upon the following factors:

(a) It has been found by experiment that when the frequency of alternating current is very low, if a current of 1 mA (milli-ampere) to 8 mA flows through a body, a person can withstand it. Current above 8 mA (1 mA = 1/1000 ampere) and up to 15 mA gives a very painful shock. Sometimes it shrinks the muscles even. If a current of 20 mA to 50 mA flows through the breast, it stops breathing. A current of 100 mA to 200 mA rends the heart. Current above 200 mA burns out the body and stops breathing but does not rend the heart.

Thus, it is seen that the intensity of electric shock depends upon the amount of current flowing through the body and consequently upon the supply pressure, as greater the supply pressure, larger is the amount of current flowing through the body.

The resistance of a human body is different under different conditions. If the body is dry, resistance per square centimetre varies between 70,000 ohms up to 100,000 ohms. But if the body is wet, this resistance per square centimetre decreases to 700 ohms to 1,000 ohms. For this reason with a dry body while a person can withstand an electric shock from a supply line, with a wet body he may even die through a shock front the same supply line.

(b) Lower the frequency of supply, more severe is the electric shock. For the same supply voltage, most severe shock is received from a d.c. supply.

(c) Intensity of electric shock also depends upon through which part of the body current flows. If the current does not flow through heart or breast, there is no possibility of respiration being stopped. But there is possibility that the body may be burnt out.

Different causes for which a person may get electric shock while working on electric line are stated as follows:

(i) If a person comes in contact with a bare conductor through which current is flowing, he will get electric shock.

(ii) If there be leakage of current through insulation of an electric circuit at a particular point and a person comes in contact with the circuit at that point, he will get electric shock. Greater the amount of leakage current, more severe will be shock.

(iii) If earthing is not effective or continuity of earth wire is not maintained, metal conduit pipe or metal sheath of wiring system may be charged due to leakage of current, and any person coming in contact with such a wiring system will get electric shock.

(iv) Through mistake if a single-pole switch is placed in the neutral line, the live line will go direct up to lamp holder or fan terminal. In that case if the metal lamp holder or the body of the fan comes in contact with the live wire, it will be electrically charged even when the switch is put off. For replacing a fused lamp or for cleaning the blades of the fan when a person comes in contact with such a charged holder or body, he will get electric shock.

(v) If a fuse wire is inserted in the neutral line and due to some reason that fuse wire melts while the connection of live line is maintained, flow of current through the circuit will be stopped and no load will operate. Under the circumstance if a person presumes the circuit to be dead and he touches the bare live conductor without putting the main switch off, he will get electric shock.

(vi) In many occasions a considerable amount of electro-static charge is left in high voltage overhead lines, cables and other equipment’s like transformer, capacitor etc. after the main switch is put off. If this charge is not properly discharged to earth, any person coming in contact with such a line or equipment will get electric shock.

Essay # 2. Precautions to be Taken while Working on an Electric Line:

While working on an electric line following precautions must be taken to avoid accident:

(1) While going to work on an electric line, one must take a neon-lamp tester or a test lamp with him. Before touching any bare conductor at any part of the wiring system, he should bring the on tester in contact with that conductor or one terminal of the test lamp should touch the conductor and its other terminal should touch the earth wire. If the tester or the lamp lights even dimly, he should not touch the conductor without putting the main switch off. Thus the causes of accident mentioned in (i) & (v) of art 10.18 may be avoided.

(2) The insulation resistance of wiring system of a house or a factory should be periodically tested by means of insulation testing megger. If the insulation resistance between conductors or between conductors and earth is found to be less than 1 megohm at any part of the wiring, the wires of that part should be replaced by new one. In this way periodical testing of wiring system helps to avoid accident mentioned in item (ii) of art. 10.18.

(3) Depending on supply voltage one or two copper or galvanized iron earth wires are to be drawn along with metal conduit line where conduit wiring is adopted. By means of earth clamps the earth wire should remain in close contact with the conduit pipes. Besides, the electrical continuity of metal conduit or metal sheath of cables can be tested with the help of an insulation testing megger.

Where one wiring line ends or where one line ends and one or more lines start, perfect bonding system must be provided among all conduit pipes or metal sheaths. With the help of an earth testing megger resistance of the whole earthing system should be periodically measured. This resistance must not exceed that as specified by Indian Code of Practice.

At any time during testing if earth resistance is found to be high, precautionary measures have to be adopted to bring it down. If the earthing arrangement of a wiring system is correctly maintained, the cause of electric shock can be avoided.

(4) After completion of wiring in a house or in a factory the polarity of single-pole switches should be tested. If it is found that the neutral line in place of live line has been connected with the switch terminal, at once the connection of wire with the switch terminal should be changed.

While changing the connection of wire with the switch terminal, it is not necessary to take out the entire length of wire from the line. If only the terminal of wire coming into the junction box from the switch terminal is connected with the live line instead of neutral line, the correct polarity of the switch will be maintained.

(5) Immediately after switching off, one should not touch any high voltage line or open terminals of high voltage machines and apparatus. Those who work on high voltage lines should carry with them a length of cable which is insulated for high pressure supply. At both ends of this cable insulation is removed from a small portion so that bare conductor is available.

After switching off, the bare conductor of the cable at one end is touched with high voltage line or with open terminals of high voltage machines and apparatus and the other end of the bare conductor is touched with earth. At once the electrostatic charge accumulated in the line or apparatus will be discharged into earth. Thus the cause of electric shock is avoided

Essay # 3. Treatment of Electric Shock:

Sometimes a person appears to be dead after getting an electric shock. But if he is properly treated and medical help is given in time, the victim can recover and come back to normal life in most cases.

In our country generally Schafer’s Method is followed for the treatment of persons suffering from electric shock.

According to Indian Electricity Rule No. 44:

(1) Instructions in English, Hindi and the local language of the district 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 as defined in clause (m) of section 2 of the Factories Act, 1948 (XLIII of 1948) in which electricity is used and in such other premises where electricity is used as the Inspector or any officer appointed to assist the Inspector may, by notice to writing served on the owner, direct.

(2) Copies of the instructions shall be supplied on demand by an officer or officers appointed by the central or the State Government in this behalf at a price to be fixed by the Central or the State Government.

(3) 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 authorized persons employed by him are acquainted with and are competent to apply the instructions referred to in sub-rule (1).

The chart containing Schafer’s Method of treatment which is available from an officer or officers appointed by the Central or the State Government at a fixed price, is given below:

Treatment of Electric Shock:

This treatment should be continued for at least five hours if necessary.

A person apparently dead may be revived by the method (Schafer’s) described below:

Remove the body from contact with the wire, cable, or other conductor by:

1. Breaking or Disconnecting the Circuit,

2. Dragging the Patient away by his coat-tails, the hands being protected by India rubber gloves or any Dry woolen material, such as a cap, folded several thickness if possible. Wood or any non-conducting material may be used.

If possible, without discontinuing the treatment, send for a doctor.  

After Removal:

Do not wait to undo the clothing.

Place the Patient on his chest with head turned to one side, Kneel at his side and, grasping the lower ribs with both hands, Gradually throw your weight on to his body, Spring quickly back, and Repeat the movement fifteen times a minute.

Do not leave the Patient or stop Artificial Respiration until a doctor arrives.,

Keep the Patient warm.,

Note:

The following Doctors or Hospitals are within easy reach of the works:

The following persons are able to apply Artificial Respiration (I.E. Rule 44):

Position 1:

Patient on chest with head turned to one side. Operator Kneeling at side. Note outstretched position of figures—the hands grasping as large an area as possible.  

Position 2:

The operator has gradually thrown his weight on to the Patient’s body, and at the same time he compresses the chest from side to side. He then springs back, relaxing all pressure on the chest.

This combined movement is repeated fifteen times a minute.