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Electrical Calculators

Wire gauge, circuit load, conduit fill, and outlet spacing calculators.

Electrical wire sizing must comply with NEC Table 310.15(B)(16) ampacity ratings and the 3% voltage drop rule for branch circuits. Using undersized wire causes heat buildup and is a fire risk; oversizing wastes money. The wire gauge calculator tells you the minimum AWG for your load and run length, and flags when voltage drop requires upsizing beyond the ampacity minimum. The conduit fill calculator applies NEC Chapter 9 rules — 40% fill for one conductor, 31% for two, 53% for three or more — to prevent heat buildup inside the conduit.