Cable — Derating Factor Table |link|

As the surrounding temperature rises, the cable’s internal heat adds to the ambient heat, accelerating insulation aging. Derating tables provide multipliers for different temperature ranges. For example, a standard PVC-insulated cable rated for 30°C might have a derating factor of 0.88 at 40°C, and 0.75 at 50°C. Conversely, at very low temperatures, the factor can exceed 1.0, allowing higher currents.

To use it:

| Ambient Temp (°C) | Derating Factor (PVC, 30°C base) | |------------------|----------------------------------| | 30 | 1.00 | | 35 | 0.94 | | 40 | 0.87 | | 45 | 0.79 | | 50 | 0.71 | cable derating factor table