In a 3-Pin Plug, one pin is larger than the rest. Why?

in a 3plug pin why one pin is designed larger than the rest,any reason for this!

the reasons are (1) that it has to operate the safety shutters fitted to the corresponding socket outlet, enabling the line and neutral pins to enter the socket, and (2) it ensures that the appliance is always earthed before it is energised and de-energised before being unearthed.

if it is wrong please correct me

these two reasons may not justify because it can be done by keeping the third plug of same size also.

Its just kept bigger to explicitly distinguish it as a Ground so you don't plug it incorrectly.


(Sorry I am not very good in drawing & things, so bear with this)

You see, you're supposed to plug-in A = GND, B = live/neutral, C= live/neutral. If both A, B & C are of same size, what's there to stop me from pluggin A = live/neutral, B=GND or any other way than it should be? You would say it idiotic to plug that way, but such mistakes do happen since humans are involved & sometimes, the curiosity bugs bite hard as well.

why earthing is needded ?????

y earthing is need???

can anyone explain me y earthing is need ????

Current always flows in the path having lowest resistance from higher potential to lower potential. Take a case where you've a device with a metallic body & a live getting shorted with it. Now, if there is no ground connected to the body of the device & you touch it, you know what's gonna happen. Here, you'll be the path having lowest resistance connected to the lower potential aka the earth.

this implies only to a device having metallic bodies..... ?????

if you are not yet sure your body offers a resistance of about a mega ohm if there is an alternative path having lesser resistance then you are safe else i don't want to say

a continuation of @[protype]'s post

not so all devices have some resistance but if that is higher than your body you are at a greater risk

in general that is the reason all devices have metal bodies

Not at all, but its highly expected in the devices having metallic body. You cannot estimate the number of ways you can get in contact with the live. A cut in a wire, a breakage in device exposing internal parts, handling with wet hands & the list never ends...

another..... a two pin plug wire which has a cut in a wire.... if get in to the contact of tht wire will i be eltrocuted????

since a two pin plug wire which has a cut in a wire.... if get in to the contact of tht wire will i be eltrocuted???? ....becoz two pin wont hav a earth ???? conection ?

BINGO! Provided you didn't wear any shoes & touching the ground with bare foot, or not lying such a way that some of your bare body part is touching the wall.

wat is the diff between transistor and radio ??????

Prefer creating your own thread with doubts that are not related to the topic of this thread. You'll be served better that way & others will also find it easily if they have similar doubts.

when the two wires get shorted
and suddenly when you touch it you yourself will be the low resistance path for current to flow