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TOOL IDB-ELE-011
Wire gauge & V drop

Desktop only

Engineering tools are available only on desktop screens.

Wire gauge & voltage drop

Minimum wire gauge for a given current over a given length within an allowed voltage drop. For battery harnesses, motor leads, and inter-board wiring.

Wire cross-section & harness AWG —
V+ 24V Load L = 1.5 m I = 10 A — mm²
Engineering notes

Formula

  • Required cross-section: A = (2 · ρ · L · I) / Vdrop
  • Copper ρ = 1.724×10⁻⁸ Ω·m at 20°C.

Practical guidance

  • Bundled wires derate 20–30% — go bigger if ≥3 wires run together.
  • For DC, treat round-trip resistance.
  • Check fusing: wire ampacity must exceed upstream fuse rating.

Result

Live