RCBO for final-circuit protection
The Siemens 5SU1356-0KK06 is a SENTRON RCBO combining overcurrent and residual-current protection in a single 2-module-width (36 mm) device. It protects a single-phase final circuit with a rated current of 6 A at 230/240 V, 50 Hz, tripping characteristic B (3–5× In for short-circuit and overload). The residual-current element is instantaneous, meaning no intentional delay — it trips as soon as the earth-fault threshold is exceeded, which is standard for socket-outlet circuits and general-purpose final subcircuits where rapid disconnection is required.
Breaking capacity and selectivity headroom
Rated breaking capacity is 6 kA per EN 60898 (the standard for household and similar installations) and 25 kA per IEC 60947-2 (the industrial standard for low-voltage switchgear). The 25 kA figure applies at 230/240 V and gives the site electrical engineer real selectivity headroom upstream — a 25 kA SCCR at the panelboard means this RCBO can safely interrupt high-fault currents without upstream devices needing to clear the fault. Energy limitation class 3 keeps the let-through energy low enough to protect downstream wiring and connected loads.
Temperature derating — the real-world rating
The 6 A rating holds at 30 °C ambient. Above that, the continuous current must be derated: 5.7 A at 40 °C, 5.4 A at 50 °C, 5.1 A at 60 °C, and 4.62 A at 70 °C. If this RCBO lives in a non-air-conditioned panel or a hot machine cabinet, the 40 °C or 50 °C row is the one that governs the load calculation — not the 30 °C headline. Maximum operating temperature is 75 °C; minimum is -40 °C, covering cold storage or outdoor enclosures.
Panel integration and mounting
Width of 36 mm (2 modular units) snaps onto standard DIN rail. Depth is 77 mm, installation depth 70 mm. Supply can enter from top or bottom — no orientation restriction. The RCBO is rated IP20 once installed in a distribution board with conductors connected, so the enclosure provides the environmental seal; this is normal for DIN-rail equipment inside a cabinet. Overvoltage category III and pollution degree 2 confirm suitability for fixed-installation panels downstream of the main distribution board.