sensor battery or accumulator and radio frequency rf transmitter the warning unit 2 comprises a rf receiver battery or accumulator not shown and video and audio alarm device when the optical sensor assembly detects the lights from a led of the appliance it activates the transmitter and transmitter emits the rf signal the receiver of the warning unit detects this rf signal and turns on visual indicator and activates in certain condition audio alarm fig4 illustrates a basic block diagram of a remote power state detector with ef sensor assembly which includes an ef sensor assembly 4 1 and warning unit 4 2 when the ef sensor assembly detects the electrical field around the power cord of appliance it activates the transmitter and transmitter emits the rf signal the receiver of the warning unit detects this rf signal and turns on visual indicator and activates in certain condition audio alarm the warning unit units can be installed near the exit door to prevent property damage if occupant forgets to turn off the appliance and leaves the building if device is on the optical sensor detects the light emitted from the led of device or ef sensor detects the electrical field around the power cord if the signal from optical or ef sensor detected the sensor activates the transmitter and transmitter sends the signal to the warning unit the warning unit turns on the visual indicator and detects if the exit door is open or closed if the exit door is open the warning unit also turns on the audio alarm referring to fig6 the remote power status indicator includes an optical.