How does a plug fuse work?
If there there was a sudden surge of electricity that originated from your mains electricity, then if you had electrical equipment plugged it, it would exceed the number of amps that your electrical goods could cope with. However, fuses are installed to protect your equipment. If there is an electrical surge which exceeds the amps your electrical goods can cope with, then the fuse will melt, meaning that the fuse can simply be replaced without breaking the intricate wires inside.