Cable Cross Section Calculator

This tool gives a fast pre-sizing estimate for cable cross section so your line can stay within an acceptable voltage-drop limit.

It is useful for feeder circuits, motor supply lines, panel outputs, and early design-stage decision support.

Current reflects electrical load, distance represents one-way physical run length, and nominal voltage defines system level. Phase selection applies single-phase or three-phase behavior.

Input data should come from field measurements, design documents, or specifications. The tool does not read live sensors, so output quality depends on input quality.

The model limits conductor resistance-driven voltage drop by finding a minimum required section. Resistance is linked to material resistivity, conductor length, and cross-sectional area.

Single-phase lines typically use a return-path factor, while three-phase lines use phase geometry coefficients. Theoretical values are then rounded up to real standard cable sizes.

Output includes theoretical minimum section, recommended practical section, and expected drop in volts and percent for the selected case.

Interpret results together with thermal ampacity, installation method, grouping, and protection-device coordination. A voltage-drop pass alone is not a complete design approval.

Example: a 32 A single-phase load over 45 m at 230 V with a 3% drop target. The tool calculates a theoretical mm2 requirement and then maps it to the nearest higher standard size.

If the same line allows 5% drop, the required section may decrease. This comparison helps balance capex, efficiency, and performance expectations.

Correct cable sizing protects energy efficiency, equipment life, and fire safety. Under-sizing can create overheating risk and unstable end-of-line voltage.

This content is for technical guidance only. Always validate final decisions against national standards and a licensed electrical engineer/expert before installation.