Research — Illustrative (draft, unvalidated)
Conductor ampacity — auto
No controls here. First the air warms from 20 °C to 50 °C in a 2 ft/s crosswind and the ampacity falls as the conductor has less temperature headroom. Then, at 40 °C, the wind rises from still air to 8 ft/s and the convection arrow swells. The tick marks the IEEE 738 Annex B reference case.
Ambient 20 → 50 °C, then wind 0 → 8 ft/s
20 °C · 2 ft/sAnnex B reference case40 °C · 8 ft/s
Reading —
Conductor cross-section, heat balance and ampacity dial
Ampacity status
Ampacity
Heat balance
Joule heating
How the check read it
Client-side port:the logic and table in this page are a TypeScript port of the harness function, checked against values exported from the Python tests. Not a live API call. Module maturity, quoted from the domain page: “Draft; outputs should not feed compliance decisions until reviewed. Only conductor ampacity and the transformer hottest-spot function are anchored to an independent published reference; the grounding decrement and surface-layer factors each match one published point. Everything else is tested for internal self-consistency only.” The numbers are a TypeScript port checked against values exported from the Python function; the sweep order is staged. The tick case (40 °C, 2 ft/s, 100 °C limit, solar 96 W/ft²) is the one the harness test compares with the ~993 A published in IEEE 738-2012 Annex B, within ±10%.Real function this maps to:
calculate_conductor_ampacity.Not modeled: elevation (fixed at sea level), conductor sizes other than Drake, emissivity and absorptivity other than 0.5, solar geometry (flat 96 W/ft²), transient or emergency-duration ratings, and the sag and clearance consequences of a hotter conductor. Fixed in this walkthrough: wind angle 90°, conductor limit 100 °C.See also:Conductor ampacity (interactive)