What this RCBO carries
The Siemens 5SU1153-6KV10 is a combined residual-current and overcurrent protective device — an RCBO — in a single 1+N-pole package. It pairs a 10 A B-curve MCB with a 10 mA Type A RCD, rated to break 4.5 kA. The 70 mm width (roughly 4 standard modular units) means it occupies a full-width slot in the consumer unit or sub-distribution board; no space left for a narrow auxiliary alongside it.
The 10 mA residual sensitivity (IΔn) is the key spec for this RCBO — it catches leakage currents well below the 30 mA threshold used for general socket-outlet protection. That matters when the circuit feeds wet-area equipment (showers, outdoor pumps, laboratory benches) where a 10 mA trip threshold provides a higher level of shock protection. The Type A designation means it detects pulsating DC residual currents, not just sinusoidal AC — needed for circuits with single-phase rectifiers, switching power supplies, or electronic loads that generate pulsed fault currents. The B-curve 10 A overcurrent element trips at 3–5× In (30–50 A magnetic), which is standard for resistive or lightly inductive loads like lighting, small heaters, or control transformers. It is not sized for motor-starting inrush — a C-curve would be the typical choice there.