A garbage disposal requires a dedicated circuit with both a 15 or 20-ampere switch depending upon the situation. The switch is used to control the flow of electricity to the garbage disposal and should be rated to handle the load of the garbage disposal. The size of the switch depends on the size and type of garbage disposal installed. A 15-amp switch is generally used for a 1/2 HP garbage disposal and a 20-amp switch is recommended for larger or higher-powered disposal.