Question

what is the earth/grounding plug for on a 3 prong device? also how does this work and what makes it different too the other two prongs? can the physics for this please be displayed in detail?

Answer 1

In a 3 prong device, one prong gets connected to neutral, another to live and the third to ground. WHen the current flows, it flows from live to neutral. ie., when an appliance with 3 pins is connected to a 3 pin socket, the current flows from live of the socket through the appliance, into the neutral of the socket, thus making the apliance alive in the process. IN other words, the appliance completes the circuit.

However, the neutral and the ground wires ultimately go the same place i.e., they all get connected to the ground. Then the question arises on why two are needed when both are doing the same job. The answer to this question is that ground protects the user of the appliance from getting a shock. Now, how is this acheived? Almost all the electrical appliances that we use come in metal casing. Assume that a wire inside the appliance gets loose and starts touching the metal case. We know that the metal is good conductor of electricity and the metal case also gets live now. The user of the appliance, when touches the metal case, will be subjected to a fatal electric shock ( ie., the current flows from the metal case, through his body into the earth ). In order to avoid this, the metal case is connected to the ground pin. in case of any wire getting loose and the metal case becoming live, the current gets shunted to earth through the ground pin. THe appliance doesnt work, but the user is protected.

Hence it is always recommended to use appliancces with 3 pin prongs.