The following is a release from the Springfield fire department.
Portable generators are useful when temporary or remote electric power is needed, but they can be hazardous. The primary hazards to avoid when using them are electric shock or electrocution, fire and carbon monoxide poisoning. There are simple steps you can take to prevent the loss of life and property resulting from improper use of portable generators.
To avoid electrical hazards, the generator needs to be kept dry. It is best to operate it on a dry surface under an open, canopy-like structure. Before touching the generator, dry your hands. When plugging appliances directly into a generator, only a heavy-duty outdoor- rated extension cord should be used. Make sure the entire extension cord is free of cuts or tears and the plug has all 3 prongs, especially a grounding pin.
NEVER plug the generator into a wall outlet. This practice, known as back feeding, can cause an electrocution risk to utility workers, those near downed wires, and others served by the same utility transformer. When connecting a generator to house wiring, always have a qualified electrician get an electrical permit and install the appropriate equipment.
To Avoid Fire Hazards, turn off the generator and let it cool before refueling. Fuel spilled on hot engine parts could ignite. Always store fuel outside of living areas in properly-labeled, non-glass containers. Store fuel away from any fuel-burning appliance.
To Avoid Carbon Monoxide Hazards, always use generators outdoors -- away from windows, doors, and vents. NEVER use generators inside homes, garages, basements, crawl spaces, or other enclosed or partially enclosed areas, even with ventilation. Follow generator manufacturer's instructions. Install battery-operated or plug-in (with battery backup) carbon monoxide alarms in your home, following manufacturer's instructions. Don’t forget to test CO alarms often and replace batteries when needed.