Kitchen Circuit Requirements
The code requires two or more 20-ampere small-appliance branch circuits for all of the receptacle outlets in the kitchen and the areas associated with the kitchen such as pantries, breakfast rooms, dining rooms. The dedicated small-appliance branch circuits are exclusively used for the kitchen wall and countertop receptacles and the ancillary areas and must not be used to supply lighting loads or any other non-kitchen areas.
The reason for this is to ensure that all of the combined capacity of the 20-ampere small-appliance circuits is available for an undetermined number of portable appliances that may be used at any one time by the homeowner. Think about all of the typical portable appliances that may be used for a Thanksgiving get-together: slow-cooker pots, fondue pot, blender, hand mixer, food processor, coffee maker, juicer, toaster oven, waffle maker and more. In the typical kitchen, the receptacle outlets that serve the countertop areas get used much more often than the wall receptacles that may be scattered around the perimeter of the kitchen or dining room area. That is why all of the receptacles that serve the countertop surfaces are required to be supplied by two or more 20-ampere small-appliance branch circuits. In other words, the receptacles for the countertop surfaces need to be divided between the two or more 20-ampere small-appliance circuits to avoid any overloading conditions that could occur if all of the countertop receptacles were only supplied by one of the 20-ampere small-appliance circuits.