Cable Tray & Conduit Sizing Calculator
Calculate fill ratio, derating factors, and recommended sizes for cable trays and conduits. Add cables, set ambient temperature, and verify compliance with fill limits and current derating.
NEC Art. 392 \u00B7 IEC 61537 \u00B7 AS/NZS 3008
Configuration
Cables (1 conductor)
| Size | OD (mm) | Rating (A) | Qty | |
|---|---|---|---|---|
| 9 | 20 |
P
Fill Ratio: 31.6%
Maximum allowable: 40% (NEC Art. 392)
0%Max 40%100%
Total Cable Area
64 mm²
Suggested Conduit
16 mm
Derating Factor
1.00
Conductors
1
Derated Current Ratings
Combined grouping (1 conductors) and temperature (30°C) derating applied.
| Cable | Base Rating (A) | Derating Factor | Derated Rating (A) |
|---|---|---|---|
| 2.5 mm² (x1) | 20 | 1.00 | 20.0 |
Calculation Notes
- Fill ratio limits: conduit 40% (>2 conductors), cable tray 50% (multiconductor)
- Grouping derating per NEC Table 310.15(C)(1) for 1 conductors
- Temperature correction per NEC Table 310.15(B)(1) at 30°C ambient
- Cable outer diameters are typical values for single-core PVC/XLPE
- Current ratings based on NEC Table 310.16, 75°C column, copper conductors