A standby generator, sometimes referred to as a backup generator activates when the power grid cuts out, literally within seconds. Depending on the size of your generator, it can provide electricity for several necessary appliances or can power an entire home, office or hospital. Who needs a standby generator? If you have a family member who is dependent on medical equipment requiring power, or an entire hospital, a generator is life-saving. Most rural homes who depend on water tanks for flushing toilets and running water should invest in a backup generator.