The Siemens 5SU1354-1KK25 is a SENTRON RCBO — a combined residual-current and miniature circuit breaker in a single 2-module-width (36 mm) package. It protects a single-phase final subcircuit against overload, short-circuit, and earth leakage in one unit, saving a DIN-rail position compared to separate MCB + RCCB. Rated 25 A at 30 °C ambient with a Type C tripping characteristic (magnetic release between 5× and 10× In), it handles motor-starting inrush and moderate inductive loads on 230/240 V 50 Hz supplies. The breaking capacity is 10 kA per EN 60898 and 20 kA per IEC 60947-2 — the higher figure applies when the device is installed per the manufacturer's instructions, giving headroom for high-fault installations. At 40 °C the continuous rating drops to 23.5 A, at 50 °C to 21.75 A, and at 70 °C to 18.25 A.
Integration & Mounting
Mounts on a 35 mm DIN rail per EN 60715 in any orientation. The 36 mm width (2 modular units) and 77 mm depth fit standard distribution boards and sub-distribution panels. Supply can enter from top or bottom — no mandatory orientation for line/load. Installation depth is 70 mm, so a 77 mm total depth means the device protrudes 7 mm past the DIN-rail clip; verify enclosure depth clearance. IP20 rating applies only when installed in a distribution board with connected conductors — the RCBO itself is not touch-proof when removed from the enclosure. Pollution degree 2 and overvoltage category III are standard for fixed-installation final circuits.
Compliance & Documentation
The 5SU1354-1KK25 is halogen-free and silicon-free, relevant for clean-room or corrosive-environment installations where outgassing must be minimized. Rated impulse withstand voltage is 4 kV, insulation voltage 264 V. The manufacturer provides the standard declaration of conformity (CE, UKCA) and the product is designed to EN 60898 and IEC 60947-2. No specific UL or CSA listing is on record for this order code.