The following picture is the starting of a circuit diagram of a house building. In which you can see that the live wire is connected to the fuse. A live wire is actually a positive wire. And Neutral wire is the negative wire. Current flows from positive terminal to the negative terminal. Hence it is first passed to the positive wire then it goes to the house and then negative terminal. So, to prevent the devices from electrical damages, fuse is connected before them. That is to live wire.