Terms of Use
Short version: use it freely, check the results, and do not treat a calculation as a compliance determination.
Use of the site
You may use these calculators and reference pages for personal, educational and commercial work at no cost and without an account. You may link to any page, quote from it with attribution, and share calculation links.
Accuracy and reliance
Considerable effort goes into making the calculations correct and the reference data properly sourced, and the calculation engine is tested against hand calculations and against published reference values. Even so, the results are estimates produced from the values you enter under the assumptions listed on the methodology page.
Verify anything that matters before acting on it. See the disclaimer for the specific limits of what these tools model.
No professional relationship
Using this site does not create an engineering, consulting or professional relationship of any kind. Nothing published here is advice about a specific installation.
Liability
The site is provided as is, without warranties of any kind, express or implied. To the fullest extent permitted by law, the operator is not liable for any direct, indirect, incidental or consequential loss arising from use of, or inability to use, this site or anything published on it.
Reference data and attribution
Conductor property, impedance and ampacity values are engineering reference data drawn from published sources, cited individually where used and in full on the methodology page. Those sources are the property of their respective publishers, and citation here is not a substitute for consulting them.
Changes
These terms may be updated. The date at the top of this page reflects the most recent revision, and continued use after a change constitutes acceptance of it.