About wiresizes.com
Who runs this site
Marko Visic writes and maintains wiresizes.com. He holds a BSc in Physics from the Faculty of Mathematics and Physics, University of Ljubljana, Slovenia.
Physics covers the measurement side of this site: conductor resistance, how it changes with temperature, wire gauge geometry and unit conversions. It does not make him an authority on the electrical code. He is not a licensed electrician or engineer, so the site reports what the code and the measurement standards say and does not give opinions on code questions.
Where the numbers come from
- NFPA 70, the National Electrical Code (NEC), 2023 edition, unless a page names another edition.
- NIST Handbook 100, Copper Wire Tables, for wire diameters, areas and copper resistance. NIST Handbook 109 for aluminum.
- NIST Special Publication 811 for unit conversion factors.
- Manufacturers' installation instructions, for pages about specific equipment.
How pages are made
Drafts are written with AI assistance. Pages are being rebuilt so that every figure traces to one of the sources above. Marko publishes every update, and when an error turns up he fixes it and adds a dated line to the list below.
Corrections
- October 25, 2026: Audited every page. Removed the unsourced claims the audit found, including user counts, endorsements, expert reviews and response-time claims, and deleted or corrected the wrong values it found. Took 15 calculators offline until they are rebuilt from verified sources. Redirected 6 overlapping or retired pages to their closest page.
To report an error, email contact@wiresizes.com.
Publisher
wiresizes.com is published by Moving Data Systems d.o.o., Smolnik 62, 2342 Ruše, Slovenia. Company registration number 9041273000, VAT ID SI94001154. Email: contact@wiresizes.com. The privacy notice lists what the site collects.