Research — Illustrative (draft, unvalidated)
Conductor ampacity vs weather
Drag the weather and the conductor temperature limit for a Drake 795 kcmil 26/7 ACSR line. The function solves the IEEE 738 heat balance for current: convection and radiation carry heat away, the sun adds some, and the current is whatever makes I²R close the gap. It computes a value; it does not judge it.
Conductor cross-section, heat balance and ampacity dial (arrow and bar widths follow the harness's W/ft)
Ambient temperature
Wind speed
Wind angle to the conductor · 90° is crosswise
Max conductor temperature
The harness flags limits outside 25–75 °C: resistance is extrapolated there.
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 default inputs are the IEEE 738-2012 Annex B case; the harness test accepts the result within ±10% of the ~993 A that standard publishes, and the port is checked against values exported from the Python function across a grid of weather and limit settings.Real function this maps to:
calculate_conductor_ampacity.Not modeled: elevation (fixed at sea level), conductor sizes other than Drake in this view, emissivity and absorptivity other than 0.5, time-of-day or latitude solar geometry (solar is a flat 96 W/ft² when on), transient or emergency-duration ratings, sag, and any clearance or loading consequence of a hotter conductor. The conductor drawing is to scale in diameter only; strands and the steel core are not drawn.See also:Conductor ampacity, auto sweep · Fault current along a feeder