Why Earth Pin is Plastic Thicker and Longer

Why Earth Pin is Plastic Thicker and Longer?

In your home you can see the three pin top which has one earth pin is longer and thicker some times in plastic. Do you know the real reason? Let see.

Remember: Earth pin is always connected in ground.

Why earth pin is thicker?

  • One most important point is safety. Because, if all of the pin in the three pin plug top is equal in size means there is a change of connecting earth pin to the phase point. This action my leads to short circuit. In order to avoid this earth pin is thicker than other two pins
  • At the same time the resistance of conductor R is ρl/A. Here the surface area is indirectly proportional to the resistance of the conductor. Hence the resistance decrease by increasing the surface area of the conductor. Decreasing the resistance of the conductor increase the path of the fault current flow.
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Why Earth pin is Longer?


Initially an electrical distribution board was installed in our home with the height of 4 feet from the ground and It was not accessible by kids.. but now a days the electrical distribution boards are installed 1.5 feet from the ground. Due to this low distance, the kids inserts some foreign materials into the socket. To avoid this, the sockets are coming with the inside shutter (protective closer). See the image…

In shutter (protective closer) socket can be opened by earth pin. Which means to insert the plug to phase and neutral terminal the shutter should open before. This action can be done by lengthy pin only. The safety point of view, the engineers decide to give the earth pin longer to open the socket shutter (protective closer).

Why earth pin is Plastic?

Some of the electrical and electronics devices/equipment does not require earthing. The device/equipment comes with the double layer protection. 100 % there is no change of electrical shocking or flash over. That’s why some of the chargers are not coming with the earth pin. At the same time some the electrical board socket is installed with protective closer, to open the protective closer the earth pin is presented.

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Example: Old Nokia Phone Charger

Watch this Video Explanation in English:


Also see:


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