General Description of Electric Shock

Electric shock is a reflex response of a body when electric current passes through it.

How does electric shock occur?

An electric shock occurs when the body comes into contact directly or indirectly with any live electric circuit and the ground simultaneously.

Electric shock occurs because of the conduction of electric current in living organisms. It could be you, an animal, a bird or a tree. As a matter of fact, electricity always flows to the ground. By its own characteristics, electricity takes the shortest route to travel. It always finds a connection, which offers less resistance (or a better conductor) for its travel.

Metals and water are good conductors of electricity. Your body contains a lot of water. So you are a great conductor of electricity. If your body touches an electric circuit and the ground at the same time; electricity will travel to the ground through you.

As a result of this flow, you may be seriously injured or killed, even if you have no direct contact to the electric circuit and the ground simultaneously. The connection may be through a metallic ladder (a good conductor of electricity).

Effects of Electric Shock:

The primary variable for determining the severity of electric shock is the electric current which passes through the body. This current is of course dependent upon the voltage and the resistance of the path it follows through the body. An approximate general framework for shock effects is as follows:

Electric Current Physiological Effect
(1 second contact)
1 mA : Threshold of feeling, tingling sensation.
10-20 mA : "Can't let go!" current - onset of sustained
muscular contraction.
100-300 mA : Ventricular fibrillation, fatal if continued.

Note: mA (milli ampere i.e. one thousandth of an ampere). Ampere is a measure of electric current. Beyond 300 mA, the flow of current to the body can prove fatal, if the shock continues. So take care. For example, a bird can sit on a high-voltage wire without harm, because both its feet are at the same voltage. Secondly the bird is not 'grounded'. You will not receive a shok by touching a high voltage wire if there is no path for the current to reach the Earth or a different voltage point. If you have insulating shoes that prevent a low-resistance path to ground, you can escape serious shock even if you touch 220-volt circuit with one hand.

The role of electric current in electric shock: The severity of electric shock is mainly determined by the electric current (the most physiological variable) in amperes. This current is dependent on the voltage and the underlying resistance, You find that a voltage some times produces a mild tingling effect where as in different circumstances, it can be a lethal shock hazard. So establishing electrical safety in such conditions is quite difficult. Does 220-volt common domestic voltage produce electric shock ? It depends.


Case 1: In normal circumstances your body resistance is say 100,000 ohms. Then the current flow would be: I = 220 volts / 100,000 ohms = 0. 0022 = 2.2 mA (This does not do any harm. It produces a tingling effect only)


Case 2: Let us say you are sweating or wet and bare footed, then your body resistance might be as low as 1000 ohms. Hence in this case I = 220 volts / 1000 ohms = 220 mA (This is a lethal shock, quite capable of producing ventricular fibrillation and death. So please be careful.

Inference: The severity of shock from a given source will depend upon its path through your body.

What is Electricity?

What is Electricity?
Electricity is the flow of current. Due to this flow, a device such as an elecric bulb glows.

Click the switch 'ON', to see the bulb glow.

Click the switch 'OFF', to stop the flow of current.

Observation: The current flows inside the bulb. Also, current is available in the circuit; when the switch is on. When the switch is off, there is no flow of current. So the bulb stops glowing.

This is what Electricity is!

By the use of electricity we can drive motors, electric fans and many electric appliances such as a toaster, a television, an electric iron etc.

Where does Electricity come from?

Electricity is produced in Power Generating Stations. It is produced by rotating thick coils of wire inside very huge magnets.

We transmit electricity through wires.

Firstly, transmission of electricity is made via wires known as 'Transmission Lines' which are strung on towers. These transmission lines terminate in various intermediate places known as 'Sub Stations'. Here the heavy voltage is reduced through a device known as 'Transformers'. Then from the transformers by the use of overhead or underground electric lines, electricity is transmitted to the 'Loadends' (streets, houses, factories, etc.).

It is basically a closed circuit through which electricity flows. We close the circuit with switches. Now, whenever, we switch on any electric appliance (say an electric fan), it works (i.e. in this case the fan rotates). When we switch off, the electric appliance is detached from the electric circuit. So there is no flow of electricity. Hence, the electric appliance does not work.

How does Electricity travel?

Electricity travels through 'Conductors'. A conductor is a material through which electricity flows easily.

Metal is a good conductor. This is the reason why wires are made of metal. Electric wires starting from generating stations to transmission lines to sub stations to transformers and finally into buildings or into your house; are made of metal.
Water is a great conductor of electricity. Please remember that your body contains mostly water. So, electricity can travel through you!

Caution: If electricity travels through you, you may be injured or even killed. So be careful!

Electricity travels in the speed of light i.e. 186,000 miles per second. So it travels much faster than you. It will give you no time to react. So, it is better and safe to be away from electricity.

What are Insulators?

Insulators are used to keep electricity in power lines. Materials like glass, porcelain and plastic are used as insulators in power lines. If the insulator breaks, the power line disconnects from the insulator and as a result of this disconnection, the electric line can fall on the ground and energize the area around. If you touch this line, you will be injured or even killed. Even if the wire falls on your vehicle, it is energized by the wire. If by chance you touch the wire and the ground simultaneously, you will be hurt or killed. So do not touch any electric wire falling out from a power pole.



Rubber and plastic insulators are used around electric wires to keep the electricity inside. So even if you touch such insulated cable, you do not get shock. If the insulation is broken or worn off, the electricity can come through and shock you. Similarly, if you overload an outlet by plugging in too many things, then due to unusual flow of excessive current, the electric wire will over heat the insulator. As a result of this the insulators will burn, which cause shock or fire hazard.

How can Electricity hurt you?

When electricity travels through you, it can hurt you. Usually electricity finds the easiest path to earth or the ground. If you are in between ground and electricity, it will travel to the ground through you and you will experience electric shock. As a result of this, you may be hurt or killed.

Global Warming

Over past centuries, we have been burning high amount of fuels such as wood, coal, oil, natural gas and gasoline. The gases emitted in this process, such as carbon dioxide, methane are building up in the atmosphere. They act like greenhouse glass trapping the heat. The result, some experts believe is the Earth heating up and undergoing global warming.

Global warming could cause:
• Global Temperature rise
• Flooding - as polar ice caps melt, raising sea levels
• Extreme weather events due to shifting ocean currents
• Deserts to spread as land dries up

Tips To Save Energy: At Home
You can quickly and easily cut down monthly energy cost and help reduce global warming:

Know How
??? Use natural light and air to the maximum extent.
?? Switch off lights and fans when you leave the room.
?? Turn off from switch point or unplug electronics, battery chargers and other equipment when not in use. These products use electricity (“standby power”) even when not in use.

Tips To Save Energy: At Work

Show leadership by being a responsible employee and save energy at workplace andcontribute in reducing global warming:

Know How?
?? Maximize use of natural light.
?? Turn off unnecessary office lights.
?? Turn off office equipment such as printers, computers, fax machines and coffee makers at night and when not in use.
?? Use laptop computers as it uses up to 90% less energy than desktop computers.
?? Set ‘sleep’ mode for computer monitors.
?? Keep windows and doors closed to prevent the loss of cooled air. Adjust blinds and window coverings on windows that receive direct sun.
?? Keep AC thermostat setting at 240C.?? Clean AC filters and ducts regularly.