The table above can be used as a guide to selecting a suitable fuse or breaker for a given power rating of appliance. The cable size shown is for the standard reference method C (assuming grey 70°C twin and earth) and the maximum length of the circuit is also shown. Other factors may affect your choice of cable size when you factor in higher ambient temperatures, different installation conditions, grouping etc.
We have a You Tube video that shows the process of choosing cable sizes in much more detail.
This can be viewed by clicking the link below.
Matching Cable Sizes