ElectriCalc Pro Calculator
The ElectriCalc Pro is the world's most complete Code-based electrical calculator. Solve electrical calculations in seconds; answers conform to current NEC. It's a complete electrical reference tool that will save time and money. Update to future code revisions with an easy-to-install kit.
More information: http://www.homedepot.com/p/Calculated-Industries-ElectriCalc-Pro-Calculator-5070/203470709