Always use the correct rating of fuse for the appliance - check the appliance instructions or the information label.
3 AMP (Red) Maximum load = 750 W Suitable for appliances such as table lamp, clocks, radios etc.
5 AMP (Black) Maximum load = 1250 W Suitable for appliances such as TV's, hairdryer, vacuum cleaner etc.
13 AMP (Brown) Maximum load = 3250 W Suitable for appliances such as fridge, washing machine, freezer, iron, kettle, toaster etc.
If in doubt consult a qualified electrician.