Smart Appliances are defined that assist in reducing energy consumption or cost. The Smart Appliances communicate with Smart Energy sources via the power lines and in particular by injecting communications signals between the live plus neutral power lines on the one hand and the ground line on the other hand, the communications protocol allowing a power source to identify the electrical circuit to which an appliance is connected and thereby to route a selected type of power to the appliance on the correct electrical circuit for that appliance.