When the need of current is more than current flowing in circuit is overloading or when too many appliances is connected in single circuit than the overloading is happen. When live wire get touch with neutral wire due to insulation failure is called short circuit
The circuit is said to have overloaded when more than the desirable load is applied to the circuit. The overload occurs because of the malfunctioning of the equipment or faulty circuits. Whereas the short-circuit condition occurs when the metal wires come in contact with each other or because of insulation failures.