On many occasions, I would forget to turn off the heater or lights in my shop when leaving. To solve the problem, I purchased a blank outlet plate and drilled six small holes to insert LED lights. After mounting the lights, I attached one leg of each of the six indicators together and connected those wires to the neutral bar on the electrical panel in the shop. I then connected the other leg of each LED to a 16-gauge insulated wire, which runs to the nonenergized side of the individual switch that needs monitoring. If the switch is left on, the LED lets me know which one is specifically energized.
Joseph Kansak | Ocean View, Delaware