What it is and what it protects
The Siemens 5SU1356-0KK13 is a 2-pole RCBO (residual current circuit breaker with overcurrent protection) from the SENTRON series, combining a 13 A overcurrent trip with a 30 mA residual-current device in one 36 mm-wide module. The overcurrent side uses a B tripping characteristic (trips at 3–5× rated current for short circuits), and the residual side is Type AC — sensitive to sinusoidal AC fault currents only, not pulsed DC or smooth DC. Breaking capacity is 6 kA per EN 60898, adequate for most residential and light commercial distribution boards.
Thermal derating — where the 13 A rating holds and where it drops
The 13 A rating is valid at 30 °C ambient. At 40 °C it derates to 12.48 A, at 50 °C to 11.96 A, and at 60 °C to 11.31 A. At 70 °C the continuous current drops to 10.01 A — roughly 77% of the nominal value. If this RCBO feeds a continuous 13 A load in a 50 °C panel interior, the breaker will nuisance-trip on thermal overload. Size the load or the ambient before locking the BOM.
Mounting and integration into a distribution board
The 5SU1356-0KK13 occupies 2 modular width units (36 mm) on a DIN rail. Mounting position is any orientation — no derating for horizontal or inverted fit. Installation depth is 70 mm behind the panel face, with an overall depth of 77 mm including the front projection. Supply can enter from top or bottom. IP20 rating applies once installed in a distribution board with connected conductors — meaning the busbar and wiring enclosure provide the touch protection; the device alone is finger-safe only when panel-mounted. Halogen-free and silicon-free construction matters for environments where off-gassing during a fault could contaminate sensitive electronics.