I am wiring up the breaker in our house for our backup generator... so I google the question but I don't get anything relevant. How do I wire up a light, LED or otherwise to my main to know when grid power has been restored? If I can figure this out, I don't see any reason I cant mount a raspberry pie or something to send a notification so I can remove the gen and return the main to grid. I would use an auto transfer switch, but I already have a manual switch sitting around, it doesn't have an indicator. I found a 220v to 5vdc stepdown converter, but not sure whats what I need, or if so, how to attach it safely. (220 into the house main). I prefer an LED, as the breaker is in a living area of the basement and prefer not to have a full on light bulb.