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