In this section we will discuss where to install the generation in relation to your home (physical distance), and with relation to your home's electrical service (the electrical distance). Both are important considerations, but for very different reasons, as you will see.
Electrical Distance - Conventional wisdom says to have your generator installed as close as possible to your main panelboard (commonly referred to as the fuse-box, breaker-box, or main panel). The basis for this guidance is to minimize the length of electrical wire needed to connect the generator into your home's electrical system. There is some benefit to this, in that longer electrical lines incur voltage drop. This means that if your generator produces 240 Volts, by the time it gets into your home, the voltage might drop to unacceptable levels. The good news is this is entirely manageable.
The current-carrying capacity of electrical wire (whether copper or aluminum) is well documented, and the National Electrical Code (NEC) provides very clear guidance on the types and sizes of wire to be used in all possible environments. What this means to you is, if you don't want to put the generator next to the house, you can put it as far away from you as you want. Before you start celebrating, remember that good things rarely come without strings (or cost) attached, and this is no exception.
Lets look at a simple example:
- Kohler 18RES generator (an excellent generator, by the way) with a derated output of 70 Amps
- The cable length from the generator into your Automatic Transfer Switch (ATS) is 15 feet
- Cable is installed in electrical conduit
If you increased the distance from 15 feet to say, 100 feet, you would need to increase the wire size to #3 Copper. This would result in a voltage drop of 2.74% -- still within acceptable limits. Just a note, if you wanted to keep the voltage drop to less than 1%, your would have to increase the wire size to 4/0. This would increase your installation cost significantly!
As mentioned above, the NEC defines the acceptable types and sizes of electrical wire for all conceivable situations. You can save money by using Aluminum conductors instead of Copper, but you have to increase the size of the conductor. Be sure to check with your state and local codes before using Aluminum. It is acceptable in most places, but there are a few special things that must be done to do the job right. We'll discuss Copper vs. Aluminum elsewhere on this site.
Physical Distance - It is a simple fact that generators make noise. High quality generators, such as the Kohler unit mentioned above, are actually pretty quiet at only 68 dB(A) -- about the same sound level as an air conditioner, some generators can be as loud as a lawn mower. Therefore, installing the generator outside your bedroom window might not be a good idea. The bottom-line here is that sound is a very subjective thing, and a quiet hum to one person is a loud noise to someone else, so be sure to take into consideration your spouse's tolerance for noise. If you like your neighbor, you might take them into consideration, too.
Fire Protection Codes - The National Fire Protection Association (NFPA) Code 37 -- "Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines (2010)", section 4.1.4, prescribes that engines must be at least 5 feet from openings in walls (e.g., doors and windows), and at least 5 feet from structures having combustible walls. In simple English, this means that you should have your generator installed at least 5 feet from your house. Your state or locality may not have adopted this standard, so you might be able to install your generator closer to your house -- but why invite trouble?
Local Requirements - It is not uncommon for local rules -- especially neighborhood covenants -- to further restrict the location of generators, so be sure to ask questions, and not automatically expect that your installer will do this homework for you.
Other Considerations - Generators produce a lot of heat, and therefore require a lot of airflow into and around the generator. Do not install your generator inside a shed, under a low deck (remember the 5-foot NFPA requirement), or attempt to hide your generator by a bunch of shrubs. Also, be sure to clear away leaves and snow, otherwise your generator WILL fail when you need it the most.