@Old_Paint, when the grid power is restored, the GenerLink disconnects from the generator and connects the house back to grid power. At that time the generator is still running but not supplying power to anything. The power in the house would momentarily disconnect indicating that it is time to shut the generator down.
We said the same thing with different words and perspective. I went to the GenerLink site to look at their product. It's a lot more convenient than having to put a transfer switch between your distribution panel and meter. That's a couple thousand bucks easy if contracted, not to mention a long outage to do the work. This thing, you get it, and have it waiting for the lineman to come cut the seal, pull the meter, plug this in, put a seal on it, then plug the meter in with another seal on that. Done in 20 minutes or less. I can see why linemen would love this thing too. The bonus is that if they pull your meter for isolation/safety, you can still get power to your house while they do their thing on the lines. On the flip side, with this device, you don't have to go turn off your main breaker. I'd like to see it with an additional time delay and some sort of output to prevent re-starting the AC, fridge, and freezer all at once, or even a blocking contact in case you don't have enough generator for the whole house. That's just the power management engineer in me.
With that device, if the lights go out, go start the generator. As soon as generator power is available, it will switch over to that. Lights back on after a very quick blink. Once Utility power is restored for a configurable time delay, flip back over and leave the generator running. If you're sleeping when that happens, you might not see it, though. With a direct feed from you're NG line, worst case, you burn a bit of NG running unloaded, which isn't necessarily a bad thing if a storm has been through. You're down in hurricane country and have to live with unstable power for a while after a biggun blows through. If you have any close neighbors, they're all gonna make long extension cords.
One other thing that I can see would be a huge plus, is the time delay for restored utility power. Sometimes, a recloser may blink the lights several times before giving up. Usually that is 4 tries then quit but may vary by Utility. Even if it were just quick blinks (tree limb on a line, Rocky the Squirrel finding out the hard way about electricity) it would prevent some of the surges to your appliances and electronics by just staying off until power was restored reliably. Get the one with surge protection, then you have double the protection. I like that feature. AC, fridge, freezer, and most anything else with a compressor or motor do NOT like surges from switching.
I assumed it didn't have anything to turn the generator off. It's normally better to let the generator run in a cool-down for a bit anyway, especially if you're running it anywhere near full rating. Besides that, I can't count the times the power comes back on, then 20 minutes later, goes off again.[/QUOTE]