What it is and where it fits
The Siemens 5SU9356-7KN10 is a 2-pole SENTRON RCBO (RCD-operated circuit breaker) combining overcurrent and residual-current protection in a single 36 mm-wide module. It is rated 10 A at 30 °C with a Type A residual-current sensitivity of 30 mA and a C tripping characteristic, making it suitable for final circuits in residential and commercial distribution boards where both short-circuit and earth-fault protection are required in one unit. The breaking capacity is 6 kA per EN 60898, adequate for most domestic and light commercial installations where the prospective fault current at the board does not exceed that level. The insulation voltage is rated 264 V, and the overvoltage category is III, meaning it is designed for fixed installations downstream of the main distribution board.
Thermal derating and mounting
The 10 A rating applies at 30 °C ambient. At 40 °C the continuous current must be derated to 9.4 A, at 45 °C to 9.1 A, at 50 °C to 8.7 A, and at 55 °C to 8.1 A. This matters when the RCBO is installed in a crowded enclosure with multiple heat sources — the derating curve is the binding limit, not the 10 A label. The device occupies 2 modular width units (36 mm) and can be mounted in any position. Installation depth is 70 mm, and the overall depth including the front is 77 mm. The supply cord can enter from either top or bottom, which simplifies wiring in tight enclosures. Touch protection is provided on the terminals. The IP20 rating applies only when the distribution board is installed with connected conductors — not a standalone ingress protection for wet environments.
Lifecycle and sourcing
The part is halogen-free and silicon-free, which may be relevant for certain environmental compliance requirements. It carries the SENTRON brand from Siemens and is classified per EN 61346-2 and IEC 81346-2 as function F.