The SENTRON 5SU1322-7KC25 is a 2-pole RCBO (residual current circuit breaker with overcurrent protection) rated 25 A with a C tripping characteristic and 30 mA type A residual current. It breaks up to 50 kA per EN 60898 and IEC 60947-2, which means it handles high fault currents in industrial panels without needing upstream fuses to limit the let-through. The 2-pole design switches both phase and neutral, so it's ready for single-phase sub-circuits in a 400 V AC, 50 Hz distribution board. Mounts in any position, takes 2 width units on the DIN rail, and its 70 mm installation depth fits standard enclosures. Conductor range covers 0.75 to 35 mm² solid or stranded, with screw terminals torqued to 2.5–3 N·m.
What the ratings mean on the line
The C-curve (magnetic trip between 5 and 10 times In) is the standard choice for motor, transformer, and lighting circuits with moderate inrush. At 25 A it'll hold a 5.5 kW motor start-up without nuisance tripping, but still clears a hard fault fast. The 30 mA type A residual detects pulsating DC fault currents — common on variable-frequency drives, LED drivers, and switched-mode supplies — which a plain AC type would miss. Breaking capacity of 50 kA at 400 V AC means this RCBO can safely interrupt a fault up to 50 kA without welding its contacts or blowing apart. In a panel with a large upstream transformer, that's the difference between a coordinated trip and a cascade failure. The energy limiting class 3 rating tells you it restricts let-through energy to a low level, protecting downstream wiring and connected loads. Rated for ambient temperatures from -25 to +55 °C with up to 95% humidity, and storage from -40 to +75 °C. Overvoltage category III means it's designed for fixed-installation panels, not just socket-outlet circuits. The 1 kA surge current resistance (8/20 µs wave) handles lightning-induced transients typical in industrial buildings.
Integration notes for the panel builder
Supply cord can enter from top or bottom — no forced orientation. The neutral conductor is switched internally, so you don't need a separate neutral bar for the RCBO's own circuit. Touch protection is built in (finger-safe terminals per the spec), which saves time on panel labeling and inspection sign-off. Halogen-free and silicon-free construction matters if the panel goes into a clean room or a zone with sensitive electronics — no corrosive off-gassing if the breaker ever arcs.