1) The line wires that are entering the meter have a voltage of 240 V
2) The minimum and maximum limit of current that can be drawn from the mains is 5 to 20 A.
3) Thus, the maximum current that we can draw from the mains is 20 A.
4) When the current drawn from the mains is more than 20 A, overheating occurs and may cause a fire. This is called overloading.
5) A short circuit is an electrical circuit that allows a current to travel along an unintented path often where essentially no electrical impedance is encountered.