Plug the heat
To facilitate the ease of attaching my furnace to the backup generator I've installed a plug on my furnace. I'm sure exactly if it's code, but the plug and socket are sized appropriately and it's electrically grounded. It should be fine. Now I can just plug my furnace into my generator. I'm sure that I will be glad and use this convenience a bunch of times (Ha!). One benefit of this is now I can get arid of the extension cord that connects the humidifier.