I invite forum members to try out the latest version of our voltage loss calculator. It's still in excel format but will be converted to web version soon (sorry no app on the horizon). The new version includes a compensator for wire temperature, so you can calculate worst-case scenarios where the wire might get overly hot or cold. BTW, crunching the numbers on that, wire resistance increases or decreases about 0.4% for every change in one degree C. That means that going from room temp (20) to freezing (0) decreases wire resistance by 8% - voltage loss decreases by that amount - of course, higher temps result in more voltage loss. Not so important for small systems, but could be important for large systems, or systems where wire is exposed to the elements (such as attached to house or fence). Also note that decreased wire resistance means that filaments and LED driver components are subject to higher spikes and surges. Yes, drivers are susceptable to the same kinds of increased inrush currents that are responsible for cold filaments to break upon start-up. Back to the calculator, to try the new version (V. 5.1), click here and select the second link (select dts file). Comments and suggestions welcome.