DC wire area from allowed drop

How it works

Required area = 2 × resistivity × one-way length × current ÷ allowed voltage drop.

Input definitions

Resistivity (Ω·mm²/m): Enter the value in the labeled unit.
One-way length (m): Enter the value in the labeled unit.
Current (A): Enter the value in the labeled unit.
System voltage (V): Enter the value in the labeled unit.
Allowed drop (%): Enter the value in the labeled unit.

A worked example

Resistivity (Ω·mm²/m): 0.0175
One-way length (m): 10
Current (A): 10
System voltage (V): 12
Allowed drop (%): 3

9.722222

Assumptions & limits

Uses only the values entered. Rates are illustrative inputs, not live quotes, legal rules or personalised advice. Check provider terms, local requirements and measurements before acting.

Sources & review

Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.

https://openstax.org/books/university-physics-volume-2/pages/9-4-ohms-law ↗

Method updated 2026-10-19. Content checked against the stated method and examples. Our verification approach.

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Common questions

Can I select the next wire size from this result?

Choose a larger standard size and separately verify ampacity, temperature, insulation and installation requirements.

How does DC wire area from allowed drop calculate the result?

Required area = 2 × resistivity × one-way length × current ÷ allowed voltage drop.

What should I verify before using DC wire area from allowed drop?

Uses only the values entered. Rates are illustrative inputs, not live quotes, legal rules or personalised advice. Check provider terms, local requirements and measurements before acting.