Why is Earth pin Thicker and longer in a 3 pIn Plug ?

Earth pin Thicker and longer in a 3 pin pug is to avoid human being for electric shock. lets know it how it works. There is technical reason to make earth pin thicker as details are discussed below. and Earth pin is longer is made longer to connect it with earth before live wire connect to main line for protection of life.

In our today life electrity is become our basic need. We use a very carefully and when there is not of electricity we must swaitch off our appliances to save electricity.

And it is very neccessry to before use of electrity we will take proper precaution to avoid electic shock from electricity. And this protection against electricity is provinding by providing propoer earthing of the electrical system and appliances.

So Why Earth pin Thicker and longer ?

We know that all electrical appliances having parts should be earthed properly to avoid human being from electric shock if any short current or leakage current flows from the metallic parts of appliances. So for the protection of Human being we make 3 Pin plug thicker.

Why earth Pin is thicker in 3 Pin Plug ?

Technically current will flow easily through a thick wire beasue resistance is inversely proportional to the area of X-section of the wire. It means when we increase the area of condutor the the resistance is decreases and same as vice versa for the condition. Because of this reation we make 3 Pin plug earth pin more thicket so that current can easilty flow from this pin in condition of short or leakage current flow from Metallic parts.

Why Earth in longer then other pin in 3 Pin plug ?

To Protect human being from Current earth pin is made longer then others pin ie Phase & Neutral. Reason are listed below

• When we insert Plug in socket first earth pin will connect with system and if any short/leakage current available in the system it will earthed.
• The earth pin should be the first to connect in Socket and the last to disconnect with electric power supply. 
• First benefit of Thicker pin is to prevent the wrong way to operate a 3 pin plug.

Technical reason of Thicker earth Pin

And second reason is law of resistance

R = ρ (L/a)   … [ Law’s of Resistance)

And we know

R denotes as Resistance

ρ denotes as resistivity

L denotes as Length of conductor

and

a denoted for area of conductor

Now Lets discuss about the above formula

Resistance is inversely proportional to the area of the conductor. i.e. thicker of the conductor, lesser is the resistance. Means if increase the dia of condcutor resistance will reduce.

So if in any case, whenever a wet body having low resistance touches the metallic body of the machine where leakage current exist. Current will flow through it as it find easiest way (having very low resistance) to complete the path. So there is still a chance of electric shock in the above mentioned case. current will flow from the earth which is having low resistance.

Why there is a cut or split in the electrical plug ?

When excessive current flow through a plug/conductor there is a bad effect on thermal expansion. So, the pins of the electrical plug are cut so that they cannot change their shape when heated. Whenever electricity flows through such pins, the power is split into two parts due to the incision, so that they do not heat up quickly.