I'm not an electrician either, but I think you want a tranfer switch between the utility power and any backup power source.
If not set up and isolated properly you can backfeed the grid through the transformer, stepping up the power, making it dangerouse to utility workers. Lineman really frown on that. Also if not done correctly and utility power is restored all your equipment may be fried as well as risk to your home circuits, fire, and electrocution. I have heard tales of linemen and power companies having uncooperative cutomers running a generator during a power outage. At least one of them insisted on not turning off and disconnecting his generator. The homeowner insisted it was installed correctly. The homeowner found out very dramatically it wasn't installed right when the utility restored power.