Cable Tray Fill
Cable-tray fill against the NEC 392.22 sum-of-diameters or cross-sectional-area allowance, with a pass/fail.
Example
You enter
- Tray type ladder
- Tray inside width (in) 12
- Cables: count,diameter(in),large|small per line count 6, diameter (in) 1.5, large true
You get
- Fill value 9
- Allowable 12
Details, formula, and sources
NEC 392.22(A): cables 4/0 and larger, sum of diameters <= tray inside width; smaller cables, sum of cross-sectional areas <= the column-2 allowable (~1.167 * width ladder/ventilated, ~0.917 * width solid bottom); mixed loads reduce the smaller-cable column-1 area by 1.2 * the sum of the 4/0-and-larger diameters (392.22(A)(1)(c), ladder/ventilated).
Cable-tray fill per NEC Article 392.22 (the sum-of-diameters rule for cables 4/0 and larger and the cross-sectional-area allowance for smaller cables), by name.
NEC is free to read at nfpa.org/freeaccess. Ampacity derating for tray fill (392.80) is a separate check.
Estimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
Field names used by the API: tray_type, tray_width_in, cables, fill_value, allowable
- Column-2 allowance the linear column-2 area the NEC Table 392.22(A) encodes; verify against the adopted tableNEC Table 392.22(A)