Concept Drafts › Free tools › DC wire size (voltage drop) calculator
DC wire size (voltage drop) calculator
The smallest copper wire size that keeps voltage drop under your limit on a DC run.
Results
Voltage drop = 2 × one-way length × current × wire resistance per foot (copper at about 20 °C). 3% is a common limit. Wire size must also meet the ampacity and code rules for its use; have an electrician confirm.
Stop working out one number at a time
A calculator is a quick check. A concept draft works these numbers out together with specs, drawings, a priced parts list, build phases and the rules to check, and updates them all when you change something.
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