Should have provided more details. You run a single circuit, probably 14/2 to a 3 way switch located above the kitchen counter for controling a duplex receptacle below the counter where you have the disposal and dishwasher plugged in. You run a 14/3 cable from the switch to the receptacle and break the tab off separating the two halves of the duplex. Now when you toggle the 3 way switch you will be providing power alternately- Switch up- disposal runs, switch down dishwasher runs. Saved the cost of a circuit and breaker.