The Siemens 5SM3616-0 is a SENTRON 5SM3 series residual current circuit breaker (RCCB) rated for 63 A at 230 V AC, 50 Hz, with a 300 mA AC fault-current trip threshold. Instantaneous-trip RCCB, no short-time delay. The 300 mA trip threshold is for equipment protection, not personnel shock protection.
The 63 A rating holds at 40 °C and 45 °C, then derates linearly: 60.48 A at 50 °C, 57.96 A at 55 °C, 55.44 A at 60 °C, 52.92 A at 65 °C, and 50.4 A at 70 °C. Mounts on DIN rail (REG) in any orientation. Occupies 2.5 width units (36 mm wide, 90 mm tall, 70 mm deep). The IP20 rating is standard for enclosed distribution boards — the busbar and conductors are finger and back-of-hand safe once the cover is on, but the RCCB itself is not sealed against dust or moisture ingress.