Explain the meaning and safety function of each of the following terms or features associated with mains electricity:

(i) The PVC outer insulation jacket on a flexible three-core mains cable.

(ii) A 3 A cartridge fuse fitted in a plug.

(iii) The protective earth conductor connected to the exposed metal chassis of an appliance.

(iv) The safety design of a Class II (double-insulated) appliance.

Modern electrical distribution boards utilise miniature circuit breakers (MCBs) rather than traditional cartridge fuses. State two operational advantages of using an MCB instead of a cartridge fuse.