RCBO with C-curve — 6 A, 1P+N, 4.5/25 kA
The Siemens 5SU1353-1KK06 is a SENTRON RCBO (residual current circuit breaker with overcurrent protection) rated 6 A at 30 °C with a C tripping characteristic, protecting a single-phase line (1P+N) at 230/240 V, 50 Hz. The C-curve (tripping between 5× and 10× In) suits moderate inrush loads like small motors, lighting banks, or control transformers — it holds through the start-up spike but clears fast on a hard fault. Breaking capacity is 4.5 kA per EN 60898 and 25 kA per IEC 60947-2. The 25 kA figure under 60947-2 is the industrial rating — it means this RCBO can safely interrupt a fault up to 25 kA when installed in an industrial panel with the upstream impedance that standard assumes. The 4.5 kA EN 60898 rating applies in a domestic or light-commercial distribution board. Either way, the device is energy-limiting class 3, so it restricts let-through energy on a short-circuit, protecting downstream wiring and connected loads.
Thermal derating and mounting
Rated 6 A at 30 °C ambient; derate to 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. In a crowded panel with internal temperature above 40 °C, the actual continuous load must stay under the derated value — the thermal-magnetic trip element responds to both current and ambient heat. Mounting position is any, so vertical or horizontal DIN-rail orientation does not affect the calibration. The device occupies 2 modular width units (36 mm) on a 35 mm DIN rail, with a depth of 77 mm and installation depth of 70 mm. Supply can enter from either top or bottom — no mandatory line/load orientation. The RCBO is halogen-free and silicon-free, which matters for outgassing-sensitive environments like clean rooms or sealed enclosures where corrosive byproducts from a fault could damage nearby electronics.