Emergency electrical generators -- love 'em. I've used many of them over the years and they sure are helpful. Aside from everyday use in the construction and outdoor industries, they are valuable at any time of the year, when storms knock your power out. That's when they are much more than just a convenience. Look below the fold for information about generators.
Generally speaking, electrical generators for emergency home use have higher capacity than those available for rental. A ten thousand watt generator has the theoretical capacity (100 light bulbs of 100 watt size) to power a good share of an average size home, one on the order of several thousand square feet.
In the unusual instance that you have a mansion or are subject to frequent, long-lasting power interruptions, you may require a generator unit much larger in capacity. Check with your electrician to determine if one of these monsters is the right generator for you; they will have a much more sophisticated hookup and switching system than for a small, residential-capable generator.
If you have a homeowner-sized generator, it may be the better case for you not to tie the generator into your home, but rather to plug your important survival items -- refrigerator, freezer, emergency radio and communications - into the unit. That will keep you from having the issue of "back feeding" your power into the local grid and subjecting repair crews to the hazard of contacting the live power that your generator is putting into the system; they will be very unhappy with that, I assure you.
So; if you don't want to run around plugging extension cords into your generator, what to do? Easy. You have a "transfer switch" installed. It is available in an automatic version, connected with a large emergency generator, or a manual version, for a smaller unit.
When the power goes out, you use the device to bring the incoming electricity from your emergency generator, instead of the utility power lines. Clearly, it's important to read and follow all the instructions for both the generator and the transfer switch, but it's a lot easier than it sounds.
You may need such items as a ground stake, or a protective weather cover, for your generator, if you have it permanently mounted outside your home; this along with about three days worth of fresh fuel (stored in a safe location, of course) and a program of periodic testing will go a long way to ensuring that when the weather threatens, you will have backup power readily at hand.
Do your homework on a generator before you buy, and discuss your needs with your electrician. Don't wait until the lights go out to find that your generator system doesn't work.