Why Earth Pin is Bigger and Thicker?

You must have seen a plug or a socket in which one pin or point is big and thick as compared to other two pins which are equal to each other. 

So why is that soo?

Here is the Answer to your question

So there are basically 3 major reason behind this and lets have a look over these.

1.Plug is inserted Properly- The plug consists 3 pin so if all pins will be equal then someone might put earth pin in the phase or neutral due to which connection will get wrong and if Earth pin is connected to phase then the current will flow in the machine outer body which can cause major damage to one touching it.

2. Earth pin will enter first and exits last- As we know earth pin is used to protect us from any leakage current in any machine's conductive body. So we must put earth pin before Phase to be safe from any fault current occurring later,and due to this only Earth pin is taken out at last so that if any fault currrnt is their then firstly supply is disconnected and then earth is remove to be safe from it.

3. Less Resistance Path- We know that for leakage current to flow we need to have less Resistance path, so have bigger and thicker pin create less resistance and leakage current easily get earthed.

So that's all for this Hope you understand it well.