US Patent 10923896 Modular electrical control system

A modular electrical control system includes a switch module, having at least an “on” state and an “off” state, configured to draw power from an AC power source and to control power delivery to at least one external load, the switch module including a detector that determines whether a neutral wire is connected to the switch module, and a removable user interface module configured to connect to the switch module and receive power from the switch module, wherein the switch module delivers a first amount of power to the user interface module when the detector determines that the neutral wire is connected to the switch module, and delivers a second amount of power to the user interface module lower than the first amount of power when the detector determines that the neutral wire is not connected to the switch module.