Wiring
Cable Ampacity Estimate Calculator
A transparent lumped steady-state thermal estimate using only parameters you enter.
02 / Estimate
Estimated steady-state thermal current
Enter all explicit parameters to calculate.
Method and boundaries
Uses a parameterized lumped thermal path and conductor I²R heat only. No cable tables, standard corrections, or installation approval are included.
FAQ
What does this calculator compute?
It estimates a steady-state current from the conductor resistance, thermal resistance, and allowed temperature rise you enter. Heat is modeled as conductor I²R on a lumped thermal path.
Does it contain a cable ampacity table?
No. There is no cable table and no standard correction factor hidden in the tool. Every thermal input has to come from you.
Is the result an installation approval?
No. Installation method, grouping, and code approval are not included.
Source records
IEC 60287-1-1:2023 (SRC-025)
Institution: IEC
Section: Product-page scope only. Standard text is not reproduced, and the page is not used as a data table.
URL on the calculation record: https://webstore.iec.ch/en/publication/68118
Verification date: 2026-10-12
Status: review-required
IEC 60287-2-1:2023 (SRC-026)
Institution: IEC
Section: Product-page thermal-resistance context only. The tool uses the thermal resistance you enter.
URL on the calculation record: https://webstore.iec.ch/en/publication/68134
Verification date: 2026-10-12
Status: review-required
NIST Handbook 100, Copper Wire Tables (SRC-027)
Institution: NIST
Section: Temperature-coefficient context only. The tool does not embed a default coefficient.
URL on the calculation record: https://nvlpubs.nist.gov/nistpubs/Legacy/hb/nbshandbook100.pdf
Verification date: 2026-10-12
Status: review-required
Transient thermal circuit model optimization for power cables with axial heat dissipation (SRC-053)
Institution: Frontiers in Energy Research
Section: Section 2.2 buried single-core soil-resistance relation. CC BY article; no tables copied.
URL on the calculation record: https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2025.1612773/full
Verification date: 2026-10-12
Status: verified (record flag, not an external certification)
Correction to the buried-cable thermal article (SRC-054)
Institution: Frontiers in Energy Research
Section: 2026 correction. Section 2.2 soil-resistance relation is unchanged.
URL on the calculation record: https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2026.1898650/full
Verification date: 2026-10-12
Status: verified (record flag, not an external certification)
Methods for rating directly buried high voltage cable circuits (SRC-055)
Institution: University of Southampton ePrints
Section: Qualitative shallow-burial context. No numeric safety threshold is embedded.
URL on the calculation record: https://eprints.soton.ac.uk/265659/
Verification date: 2026-10-12
Status: review-required
IEC 60287-2-1:2023 (SRC-026)
Institution: IEC
Section: Product-page thermal-resistance context only. The tool uses the thermal resistance you enter.
URL on the calculation record: https://webstore.iec.ch/en/publication/68134
Verification date: 2026-10-12
Status: review-required