Amazon.com description: Product Description: Understanding electrical formulas is one of the most important tasks facing today's electricians. Accurate calculations make for proper code compliance and safe installations. That's why the DEWALT Wiring Quick Check: Extreme Duty Edition will prove to be a valuable resource in the toolboxes of electricians, contractors, and others in the electrical field. The book compiles the most commonly used formulas and simplifies them, using a step-by-step approach and practical, real-world examples. Topics range from Ohm's Law and power formulas to areas of conduit and conduit fill. With easy-reference tabs and a sturdy design, this is the certain to be a beneficial tool that will stand the test of time and weather a variety of jobsite conditions.