The Siemens 5SU1636-7FP20 is a SENTRON RCBO — a combined residual current circuit breaker with overcurrent protection — in a 3-pole, 20 A C-curve configuration with a 300 mA type A residual current trip. It breaks fault currents up to 6 kA per EN 60898, which covers the standard domestic and light commercial fault-level requirement in 50 Hz networks.
The 300 mA residual current type A detects sinusoidal AC and pulsed DC fault currents, which covers most modern electronics and variable-speed drives downstream. At 40 °C ambient the continuous rating derates to 19.5 A, and at 60 °C it drops to 18.4 A — the 20 A nameplate is at 30 °C. If the panel runs warm, size the upstream protective device for the derated figure. The RCBO occupies 3 modular width units on a DIN rail, with 54 mm width and 72 mm depth plus 70 mm installation depth.