A fuse is the most basic form of protection in any electrical circuit. It is a thin wire used at the supply point in series with the circuit. When there is an overload in the system, likely to cause damage to the connected device, the fuse protects them by melting. Fuses are mounted on insulated holders, which can be either porcelain or Bakelite to facilitate replacement when required.
Fuses protect equipment and surroundings from accidental fire by blowing off and preventing power from reaching the load. For safety, fuses are enclosed in fuse-boxes. HRC (high rupturing capacity) fuses are commonly used along with switches in power circuits to cater to high current loads such as big motors.