It's a common misunderstanding that when you use the sales tax tables you can add the tax on "major purchases" or "large purchases" to the amount from the tables. This misunderstanding is perpetuated by TurboTax's use of the term "major purchases." What you are allowed to add, according to IRS rules, is the tax on "specified items." The specified items are a motor vehicle, an aircraft, a boat, a home, or a substantial addition to or major renovation of a home. This is a very simplified list. See the IRS instructions for Schedule A for details and limitations. But a generator is not a specified item, so you cannot add the sales tax on the generator to your deduction.
