Cable Tray Fill Calc

About this app

Built for electricians, cable-tray installers, and EEs who need a quick NEC 392 fill check on the deck - not a dashboard you log into. WHAT IT DOES Computes total cable cross-section as a percentage of tray area and compares against the NEC 392 maximum fill: 50% for ladder and wire-basket trays, 40% for solid-bottom and channel trays. Flags over-fill and shows how many more cables of the same type fit before the limit. INPUTS - Unit system: SAE (inches) or Metric (mm) - Tray type: Ladder, Solid Bottom, Wire Basket, Channel - Tray size: 9 imperial sizes / 9 metric sizes - Cable type: AWG #14 to 4/0 (SAE) or 1.5 to 50 mm² (Metric) - Cable count RETURNS - Tray area (sq in or sq mm) - Total cable area (sq in or sq mm) - Fill percentage - Maximum allowed fill per NEC 392 (50% or 40% depending on tray type) - Remaining capacity in number of cables - Over-fill warning (red banner) when above the allowed percentage WHY THIS APP, NOT THE FREE ONES - Math is shown - tray area, total cable area, and the percentage all visible. - NEC 392 fill limits applied automatically - pick the tray type and the cap follows. - Works offline - basements, riser shafts, mid-deck rough-ins. Always available. - No login. No ads. No telemetry. No subscription. PRICING $4.99. Pay once, own it. Lifetime access on iPhone, iPad, and Mac via Family Sharing. NOT A SUBSTITUTE FOR AHJ-stamped electrical drawings. Manufacturer cable-tray load tables. NEC 392 ampacity derating for closely-spaced multiconductor cables - this app handles cross-section fill only, not the temperature derate. Always cross-reference the engineer-stamped layout.

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1. First observed Oct 2, 2026 · 7:51 PM $7.99