1. A method for using a processor to automatically generate a service alert for an electrical device connected to a power supply, the supply also connected to a plurality of other electrical devices, comprising: providing to the processor a set of predetermined features and feature values of the turn-on transition of the device, the set of predetermined features and feature values selected such that a turn-on transition of the device is differentiated from a turn-on transition of any of the other devices when the corresponding predetermined features and feature values are compared, identifying to the processor a key feature from the set of predetermined features of the device, the key feature indicative of a need for service, providing to the processor a service alert threshold value of the key feature of the device, providing to the processor digital samples of the supply output power and voltage, providing to the processor instructions to process the digital samples to recognize a turn-on transition of the device and of the other devices and to compute the predetermined features and feature values of the turn-on transition, providing the processor instructions to identify when a turn-on transition is a turn-on transition of the device, and if identified, compare the key feature value of the turn-on transition to the alert threshold value, and if the alert threshold value is exceeded, generate a service alert.