What is Electric current? What are Phase and Neutral? What is the use of Earthing wire?

The flow of any type of material is called current. The flow of water in the ocean is called ocean currents, just like that the flow of electrons in the conductive wires is known as electric current. This is measured in Ampere, often denoted with the letter 'A'. 

In a second at around 6,250,000,000,000,000,000 electrons flow through the wire, which can be written as 6.25×10^18 e/sec.

Who makes these electrons move? It’s Voltage, who does this good job. Voltage is responsible for the flow of electrons in the conducting wires. The higher the voltage increases the good is the electric current flows. Voltage or volt is denoted with capital 'V'. 

There is the presence of another factor that opposes the flow of the electrons, known as resistance. It is denoted with the Greek letter Omega or simply as Ohm, named after George Ohm.

Different metals show different characteristics and act differently to this resistance, calling for tungsten that glows with bright light and hence is used in filament bulbs, likewise, nichrome that gets red hot and is used in room heaters, etc.

Phase wire/ live wire (comes in a red insulative coat) is the path that makes the flow of electric current possible to our homes and to different locations from the electricity supply company. And the neutral wire (denoted with the color blue or black) is that path which the electric current traces back. 

If the current doesn't get any path to return it won't work, and we call the circuit a broken circuit where the neutral wire is absent or broken. 

Earthing wire is used to discharge the extra phase that is present in the electronic device/ machine due to leakage in the phase wire. Earthing wire is green in color and is the topmost pin (largest of all three) in the electrical plug.