So, why not just point a web cam at the generator's control panel?

Or investigate this kind of thing:
http://www.greenenergyoptions.co.uk...o/home-energy-monitoring-systems-electricity/

Neither of the devices in the link are available in my country and pointing a webcam will drink too much of bandwidth

Edit - If there is any generic name for the device in the link i could surely search for that

 

A webcam will not necessarily consume a great deal of bandwidth as you only require a very low refresh rate and the image, for the most part, is stationary.

 

Still, could there be a device which i originally mentioned which could glow with a different color each time it was powered on?

All other solutions look a bit complicated

Thanks

 

What did the gen. techs say about time gaps in changeover??

 

Can you see the generator out your window (we already established you cant hear it)? If yes, mount a lamp on the top of the generator

My farmer neighbor operates an irrigation circle. It has a 75W incandescent lamp mounted on the center pivot. I can see that from over a mile away...

 

One of these will do the job... http://www.macromatic.com/products/products.php?series=ARP120A6
but I fail to understand why you need to know the source. Depending upon load, my power may come from several power plants that are sharing to the grid and it makes no difference which supplies the most.
It would be more important to me to know if power had been OFF and for how long. A non-digital clock would give me that info.