Grounding pin is larger in size why

[mqasim33]

Why size of ground pin is larger than other two pins in three pin Plug??

 

[dick_freebird]

Perhaps so that no determined idiot can make the chassis
"hot".

 

[keith1200rs]

In UK plugs the earth pin is longer so when the plug is removed the earth is the last thing to be disconnected.

Keith

 

[faiza84]

there are some reasons for this
1) The wire that is connected to ground pin of a plug is connected to the metal body of the equipment.
(Be it your iron box, microwave etc)
Any leakage current appearing on the metal body of the equipment must be discharged safely to ground so the user (You) do not get any electric shock when using the equipment.
If there is any serious fault on the equipment, it also makes the fuse blow, saving the user (you)

The ground pin is longer so when you insert the plug, the earth connection is made to the equipment first.
When you remove the plug, the earth connection is removed last.
This is for the user safety.

It is bigger so you can not insert the plug in any other way. The smaller pins on the plug can go into the larger hole, but the larger pin will never go into a smaller hole. So any live wire cannot be connected to the body of the equipment.
This is for user safety.
However the earth wire in the socket should be connected properly to the ground system.
Without this, the risk remains. Be sure you use a licensed electrician to do wiring.
Cheap labor, or any DIY lobs, the risk is your or one of your family life.

2)the earth pin must be thicker than the other pins because
the leakage current or short circuit current passes through
the earth pin will 5 to 10 times higher than the phase
current....

3)actually earth socket has large diameter as compared to
phase and neutral.

it is for the safety.

whenever abnormal condition occurs, abnormal current
should be earthed quickly and for that resistance of path
should be minimum and

resistivity = R*l/A ;
resistivity inversely proportion to area:A

so when earth socket hole be large abnormal current goes to
zero without any accident.

 

[ArNvC]

it ensures that the appliance is always earthed before it is energised and de-energised before being unearthed.

 

[tpetar]

Keith give good answer in post #3.