The present invention is directed to an electrical wiring device that includes a housing assembly having a plurality of terminals at least partially disposed therein, the plurality of terminals being configured to be coupled to an AC power source and at least one electrical load, the plurality of terminals being configured to provide the electrical wiring device with regulated AC power in a device energized state. At least one variable control mechanism is coupled to the housing assembly, the at least one variable control mechanism being configured to regulate power to the at least one electrical load by way of a control knob being user settable between a first adjustment stop and a second adjustment stop. A user accessible calibration button is included. At least one series pass element coupled to the at least one variable control mechanism, the at least one series pass element being configured to provide load power to the at least one electrical load in accordance with a user setting of the control knob. A regulation circuit is coupled to the user accessible calibration button and the at least one series pass element, the regulation circuit being configured to enter a calibration mode when the control knob is at or near the first adjustment stop or the second adjustment stop and the user manually actuates the calibration button, the regulation circuit establishing at least one pre-determined load power setting when the calibration button is actuated when the regulation circuit is in the calibration mode.