Your generator can be set up to power as much or as little as you require.
Portable generator – in times of emergency a portable generator is started and an extension cord is run into the home through an open door or window. Additional extension cords are required to service loads that are spread around the home.
Manual transfer panel coupled with portable generator – a portable generator is connected to a permanently installed generator panel that is wired through the building’s main distribution panel. When a power failure occurs the generator is started and the transfer panel is manually switched to the standby mode. This safely disconnects the building’s circuitry from utility power and transfers it to generator power. Since the building’s internal wiring is used, there is no need to run extension cords around the building. When utility power is restored the generator must be shut down and the transfer panel is manually reset to the normal mode (utility connected).
Automatic standby generator – This generator is permanently installed and connected to an automatic transfer panel which is tied to the building’s main distribution panel. When utility power fails, the generator automatically starts itself and powers your home through an automatic transfer panel. When utility power is restored the generator will automatically shut down and return your homes power to the utility. You will never be out of power for more than 30 seconds.
Portable standby generators have two chief advantages – flexibility and cost. Due to its temporary nature, a portable stand by generator requires no permanent installation and therefore costs less. Portable generators are not expensive. These gasoline powered generators (with run times of about five hours between fill ups) come in many sizes and some are whisper quiet. These generators are portable and can be taken to a job site, cabin, or you can lend it to your friend.
This type of system requires no extension cords and the set up time is greatly reduced. A licensed electrician needs to install the manual transfer switch next to the circuit breaker panel. The portable generator can now be connected to your building’s permanent electrical system in time of emergency. You can select which circuits you would like to energize, such as your furnace, kitchen outlets, refrigerator, microwave, computer, TV, etc.
There are many advantages to an automatic standby generator. The major advantage is “automatic”. When utility power goes out the generator will start itself and restore power to the building in 30 seconds. There is no outdoor setup required with gasoline cans and flashlights in the dark. The tank never needs to be topped off because the generator runs on natural gas or liquid propane. Another advantage is this generator will start even if you are not at home, preventing pipe freezing, food spoilage and sump pump failure.
An automatic standby generator works by monitoring utility voltage 24 hours a day, whether you’re home or away. When your electricity is interrupted, the generator detects the problem and goes to work. The automatic transfer switch safely disconnects the utility line and transfers to generator power. Power is simultaneously restored within seconds. Once the utility is restored, the generator returns to standby mode.
Excellent question. Here’s a link to Guardian’s own series of common questions and their responses.