Cable Derating Factor Table As Per Iec Here

| Burial Depth | Derating Factor ($K_4$) | | :---: | :---: | | 0.5 m | 1.02 | | | 1.00 | | 1.0 m | 0.98 | | 1.25 m | 0.96 | | 1.5 m | 0.95 |

Note: IEC 60364-5-52 contains over 20 different tables for grouping based on installation method (trefoil, flat, in conduit, on cleats, etc.). Always verify the specific "Reference Method" code (e.g., Method F, Method E). cable derating factor table as per iec

Don't just apply one factor. Multiply them (Temp x Soil x Grouping). If your result is below 0.7, you likely need to upsize the cable. | Burial Depth | Derating Factor ($K_4$) |