How Conductor Resistance Affects Losses

When this applies

Use this guide to connect conductor geometry and temperature to resistance, voltage drop, and loss awareness during early electrical design work.

Tool to use

DC resistance from length, area, and Cu/Al resistivity with temperature correction.

Open Conductor Resistance Calculator →

Steps

  1. 1Start with conductor length, cross-sectional area, material, and temperature basis.
  2. 2Compute resistance for the conductor path you are assessing.
  3. 3Use that resistance in downstream voltage-drop or loss calculations.
  4. 4Check how temperature and smaller cross-section assumptions change the result.
  5. 5Move to code-based sizing, grouping, and thermal checks for final design.

Examples

  • Comparing copper and aluminum conductors for a feeder concept.
  • Estimating whether a hotter conductor assumption materially increases losses.

What to avoid

  • Mixing mm^2 and m^2 in the same formula chain.
  • Forgetting that temperature raises resistance.
  • Treating resistance-only results as a full AC impedance study.

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FAQ

Does this replace ampacity calculations?

No. Resistance is only one part of conductor selection and does not replace code-based ampacity methods.

Why is temperature included?

Because conductor resistivity changes with temperature and that can materially affect losses and drop.

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