This is some useful information from FPL

Fixed, installed generators
Hire a licensed electrician to connect the generator to your house wiring using a transfer switch to prevent your generator from backfeeding utility lines and causing possible damage to your generator when utility power is restored

Portable, gasoline-powered generators
Thoroughly read and follow the manufacturer’s instructions to avoid dangerous shortcuts and ensure the safe operation of your generator

Set it up outside, away from all open windows, including neighbors’ windows, to prevent deadly exhaust from entering a home or business

Use a heavy-duty extension cord rated for outdoor use to keep the generator safely outdoors. If the appliance has a three-prong plug, always use a three-prong extension cord

Consider using a battery-operated carbon monoxide alarm to be alerted if carbon monoxide levels become dangerous

Connect appliances directly to it. Do not wire your generator directly to your breaker or fuse box, because the power you generate may flow back into power lines and cause severe injuries, or even kill a neighbor or utility crew working to restore power

Turn off all connected appliances before starting your generator

Turn connected appliances on one at a time, never exceeding the generator’s rated wattage

Don’t touch a generator if you are wet or are standing in water or on damp ground

Never refuel a hot generator or one that is running – hot engine parts or exhaust can ignite gasoline

Ensure you have plenty of gas for operation stored safely in gas containers

Don’t leave a running generator unattended; turn it off at night and when away from home

Tip: Refrigerators may only need to run a few hours a day to preserve food. Try to maintain 40 degrees in the refrigerator compartment and zero degrees in the freezer.