Why the ground pin is bigger in case of three pin plug?

Normally, If you want a bulb to glow or to run a machine you will definitely require two things  Phase & Neutral.

Let us see what is a phase and neutral line

• Phase line is nothing but the supply(voltage and current) passing through the line.
• The neutral line is nothing but it doesn't carry any supply but it helps to close the circuit when a load is connected to the phase.

So, when a load(bulb) is connected to the(socket) phase and neutral, supply gets passes through the load through the phase line and the neutral line closes the circuit. Therefore the bulb consumes the supply and it glows!!!

It is known as Two plugs and it looks like this

Did you ever notice the one that we are using in our day to day basis but most of us didn't know why it is in that shape or that much big...................found it?

Three plug pin

Which is nothing but a Ground pin 

Did you ever think about why the ground pin is longer &bigger than the other phase and neutral pins?

• Let's see why it is longer & bigger and why it is important for the heavier load appliances?........in an appliance, phase and neutral plays a vital role in running a machine and what is the role of the bigger pin? Ok, running a machine by giving the supply is ok but if some problem occurs and the excess current passes through the load are considered as leakage current. 
• Suppose if the leakage current passes through the load it flows the current through the full body of the load. 
• In case of leakage current passes through the body of the load when the user intends to touch the body of the load, the full leakage current passes through the body of the user which leads to occur shock throughout the body.

• To avoid such danger conditions ground pin was included in high voltage types of equipment. 

• This ground pin discharges the leakage current from the equipment to the ground.

Ok, we have seen the importance of ground pin and next, let's see the reason for its appearance and size.

• The size of the ground pin is bigger when compared to other pins it is because that when the area of the pin is bigger which means lesser the resistance which is helpful to carry a large amount of leakage current from the load and also another reason is if the three pins are of the same size it is difficult for us to understand which pin is ground and which is a phase and neutral.

• The reason for longer the size is when the user tends to connect the plug to the socket, ground pin first enters the socket which ensures the safety and suppose if the leakage current passes through the socket ground pin discharges it. And also ground pin came out last when you plug out from the socket this ensures the safety of the user which discharges the leakage current if exists!!..