Service
NEC 392.22(A)(B) ≤2000 V
Tray
Cables
Typical catalog OD — replace with the cut sheet
| Name | Qty | OD | Class | Area | Remove |
|---|---|---|---|---|---|
| 7.47 in² | |||||
| 5.97 in² | |||||
| 1.13 in² |
Governing fill
51%
Within the selected code limit
- Cables
- 11
- Cable area
- 14.57 in²
- Section
- 72.00 in²
- Occupancy
- 20% of W×D
- Allowed area
- 9.91 in²
- Allowed width
- 18.00 in
- More 12-3 MC
- 0
Circles are packed in layers, largest first — labels sit on the cable, not in a legend. Dashed outline is overflow. Service color: telecom, control, LV copper, MV oxide. Multiconductor jackets may touch — 392.22 fill does not require a gap between them. Hatched columns are the required space above the single-layer (no stacking). The small-cable area table deducts 1.2 × Σd of the 4/0+ layer.
Checks
- Smaller-cable area (mixed with 4/0+)PASS
1.13 in² ≤ 21.00 − 1.2×9.24 = 9.91 in².
NEC Table 392.22(A) Col. 2 (Col. 1 − 1.2 Σd)
- 4/0+ single-layer widthPASS
Σ OD of 4/0+ = 9.24 in ≤ 18.00 in. No cables on top of the 4/0+ layer.
NEC 392.22(A) Σd ≤ width
- Side-to-side: may touchPASS
Multiconductor fill is a width and area check. Jackets may touch. Required space is the unused depth above the 4/0+ / MV layer (no stacking), not an air gap between cables. The 1.2 × Σd factor (mixed) reduces remaining area for smaller cables — it is not a physical gap.
NEC 392.22(A)
Heat — FEA
Each line has its own day. The temperature is the hottest hour of the mix.
80°C
4/0-3 TC-ER
% of this line’s peak. Drag its trace.
Hour 0 is midnight. The bright trace is the selected line. Faint traces are the others. Bottom is the lumped conductor temperature of the mix. Margin 10°C · hottest 4/0-3 TC-ER. Steady peak would be 84°C.
2-D finite volume per meter of tray. Each line has its own day. The trace is a lumped 24 h transient of the summed I²R; the section is that hottest hour, not every line at peak together. Geometry is the fill packing (jackets may touch). Open top uses a higher convection coefficient. Ladder, steel. Reference current is NEC 310.16 75 °C copper, scaled by each line's peak load. Not a tray-ampacity table and not IEC 60287.