Thermal derating — the real-world current limit
At 40 °C it derates to 15.2 A, at 50 °C to 14.24 A, and at 70 °C to 12.32 A. If the panel runs warm — say a crowded enclosure with drives or transformers — the actual continuous load must stay under the derated figure. The derating curve is published for every 5 °C step, so you can size the branch circuit without guesswork.
