When does an electric short circuit occur?
An electric short circuit occurs when the live wire and the neutral wire come into direct contact with each other. This happens when the insulation of wires is damaged or there is a fault in the appliance.
In such a situation, the current in the circuit abruptly increases. This sudden rise in current can cause damage to the appliances and the circuit. An electric fuse is used as a safety device to prevent such damage by melting and breaking the circuit when unduly high current flows through it.
Explanation
The textbook clearly defines short-circuiting in the context of overloading and fuse protection. It states that short-circuiting occurs when live and neutral wires come into direct contact due to damaged insulation or appliance faults, causing an abrupt increase in current.