Some appliances, such as electric cookers, have a power load greater than 3000W (3kW). These cannot be wired into the ring main because they would overload it. Cookers are generally about 8kW, but there are bigger ones with loadings up to 12kW, which need to be installed on their own 30-amp circuits run in 6mm sq. two-core and earth cable protected by 30-amp circuit fuse.
A cooker with a loading of more than 12kW will need a 45-amp circuit run in 10mm sq. cable and a 45-amp fuse. Each separate radial circuit needs its own fuseway: often in new consumer units there are one or two spares for this purpose, or you can fit an individual switch fuse unit. This will do exactly the same job as your consumer unit, but it will only be 'looking after' one appliance. If you choose the individual switch fuse, choose one with an MCB.
