The Siemens 5SU9356-1CN16 is a SENTRON RCBO — an RCD-operated circuit breaker combining overcurrent and residual-current protection in a single 2-MW (36 mm wide) module.
The breaking capacity is 6 kA per both EN 60898 and IEC 60947-2, which covers most residential and light commercial fault levels in a 230/240 V AC network. De-rate the continuous current as ambient rises: 14.9 A at 40 °C, 14.1 A at 45 °C, 13.8 A at 50 °C, 13.3 A at 55 °C — so if the panel runs hot, size the upstream breaker accordingly. The IP20 rating (with distribution board installed and conductors connected) means the breaker itself is finger-safe but not sealed — it belongs inside a closed panel.
Depth is 77 mm, installation depth 70 mm — check enclosure depth if retrofitting into a shallow consumer unit. Mounting position is unrestricted; the breaker can be installed upside-down without affecting performance. Halogen-free and silicon-free construction avoids corrosive off-gassing in sealed enclosures.