We use the fuse only in live wire and not on neutral wire.
The object of the fuse is to break the circuit in such a way as to stop the current flowing and make the circuit safe. the neutral break will stop the current flowing, but leave the circuit at the potential of the line, therefore it is not safe. severing the line relationship reaches both goals.a fuse is used to break an electrical current in the event of a short circuit or an unintended electrical hazard.
Likewise for electrical systems we need to isolate the resources i.e live wire. switch board can be considered the same as a water tank from which electricity is distributed to various equipment. on switch board, after main power, there is one fuse connected in series and then power is distributed to all equipment, power plugs, etc.
The underlying main idea is to isolate non-neutral sources. there may be an infinite number of return paths to the ground for live wires. so use one fuse for live wire instead of using an infinite number of fuses for all neutral / return paths.
There is actually a layer of protection in the electrical system and the fuse / circuit breaker is used in each layer – like a fuse in the incoming supply before the power meter. after that mcb at receiver end after power meter etc. you for asking.to prevent an electric shock.
A live wire (phase) is a cable used to supply electricity to a device. neutral acts as a way back to complete the circuit.if the fuse is given to the neutral wire, after the fuse breaks out, there is still electricity coming from the wire (phase) of life through the appliance until the fuse. Touching the appliance may cause a severe electric shock, due to an appliance error.