Electricity Myths

1. Earth conducts electricity well, that is why installations are grounded.
=> Earth/ground is an absolute insulator. There is no actual current path provided under soil. When certain current flows to the ground conductor, what happens is, it is dissipated step-by-step - depending on the soil resistivity. It is further influenced by the soil's moisture content, presence of materials such as coal, concrete, stone, carbon compunds etc. In other words we can claim that Earth acts as a very large current source and current sink -BUT it does not conduct electric current - as it isn't a conductor.

2. There will be no current flow in neutral wire in AC installations.
=> When considering a domestic installation, if you put a tester in the LIVE terminal it illuminates, but not in the Neutral terminal. This does not mean when particular appliance is connected there will be no current. It's not true. When the appliance consumes power (i.e. current) , the exact return current will be flowing through the Neutral wire. BUT it should be noted that Alternating Current (AC) osillates between two L, N terminals every 10 ms. So techically speaking after turning on an equipement - Live or Neutral does not matter. That is why there is no terminal arrangement for AC wires. You can connect the apparatus to anyone of the two-wire terminals.

3. High voltage shock is dangerous to humans; NOT high current.
=> You can't really say it's the Current or Voltage that harms a human by passing through the human fluids/muscles/bones and leads to fatality. Normally 50V of voltage and 30mA of current is considered the threshold of DANGER. But it is not clearly defined. This is becuase both CURRENT and the EXPOSED TIME determines the severity of the damage caused. Most claim that welding transformers having high currents and 50V potential normally does not endup in casualities. Similarly exposure to small leakage currents arising from very high voltage lines also treated as not-harmful.(There is a small leakage current under a 132kV transmission line). But it should be noted that grabbing a LIVE wire of a 230V domestic supply will make you injured in seconds. So technically speaking the possible danger is a function of Voltage, Current and Time. So in mathematical terms:
DANGER form electric shock ----> is proportinal to ---> f(V, I, t)