Abstract: Interface circuitry for facilitating the installation of a control device is presented. One embodiment includes an interface circuit with first and second terminals that can be coupled interchangeably to a load and the utility hot of an AC power source, thus eliminating the time-consuming requirement that a particular wire be coupled to a particular terminal. The interface circuit also limits the amount of current supplied to the control device during periods of low current demand, thus reducing current and power consumption. An additional feature further facilitates installation of a control device when that device is being installed in a metallic electrical enclosure that is itself coupled to utility return. The device's return terminal is automatically coupled to the power source's utility return upon mounting of the control device in the enclosure.