(N/A) Short-circuiting occurs when the live wire and the neutral wire come into direct contact with each other. This happens due to $(i)$ damage to the insulation of the power lines,or $(ii)$ a fault in an electric appliance. Due to short-circuiting,the resistance of the circuit decreases to a very small value,causing the current to become extremely large. This high current results in the heating of the live wires,which produces sparking at the point of contact. This sparking can sometimes cause a fire in a building.
An electric circuit is said to be overloaded if the total current drawn by all the electric appliances connected to it exceeds the permitted limit of the circuit. Overloading results in excessive heating of the wires,which can damage the insulation and lead to electrical fires.