Residual current unit for panel integration
The Siemens SENTRON 5SM9625-6KK is a 2-pole residual current unit (RC unit electronic) in the 5SM9 design, rated 63 A at 230/400 V AC, 50 Hz, with a tripping residual current of 300 mA, type A.
Current derating across temperature
Rated current holds at 58.59 A up to 45 °C, then derates stepwise: 56.7 A at 50 °C, 54.81 A at 55 °C, 53.55 A at 60 °C, 52.29 A at 65 °C, and 50.4 A at 70 °C. If the panel ambient runs above 45 °C — common in a crowded enclosure or near heat sources — the continuous load must be reduced accordingly. For a 63 A nominal circuit, the headroom at 70 °C is 50.4 A, so a full-load 63 A feeder requires derating or forced cooling above 45 °C.