Hi, I have a small generator. I'd like to wire a clean interface so that I may power a furnace and a couple of appliances during a winter power failure (without breaking the bank). Below is a drawing of how I thought I might do it. I'm not sure if the ground is sufficient (it's 12 gauge ground wire) or if I should run a dedicated ground back to the panel. Also I know it's not code to put a plug on a furnace but it will still be on a dedicated circuit. What are your thoughts?