We hired a company based in Columbus, Ohio to install a Generac 20KW back-up generator which runs on natural gas at our home in January 2010 after receiving a coupon in a monthly mailer. We checked the company on the Better Business Bureau web site. While they were not perfect, all complaints had been resolved at the time. When the installer was unresponsive to some maintenance issues after they performed the first year's annual maintenance service, we hired Riverside Electric in February 2011 to perform the annual maintenance going forward. A warranty issue with the starter arose before 2012 maintenance would have been due, and Riverside came out promptly to take care of the issue. In doing so, they advised that they believed the wiring done by the original installer to be faulty and not code compliant. Furthermore, the generator had not been installed on a level surface as is the best practice recommended by the manufacturer. Riverside advised us to obtain an electrical inspection of the original work by IBI and, when the work failed IBI's inspection, we would then be able to require the original installer to correct the defective work at the installer's expense. We did so, but discovered that the original installer had gone out of business. Riverside performed the work necessary to correct the original installer's faulty work. Riverside was not inexpensive, but the work was far more complicated than an original installation would have been. First Riverside had to undo the faulty work, and then rewire everything correctly. Our advice to anyone who has had a back-up generator installed without first obtaining an electrical permit would be to obtain the permit after the fact as soon as possible, and have the work inspected to make sure it is code-compliant. If it is not, then require the original installer correct the work now, before attempting to sell the home in the future when the original installer may be out of business by that time.