What this RCBO is and what it does
The Siemens 5SU1353-1WM08 is a 1P+N RCBO — a combined residual current device and miniature circuit breaker in a single 2-module-wide unit, part of the SENTRON 5SU1 family. It protects a single-phase final subcircuit against earth leakage (30 mA, Type AC) and overcurrent/short-circuit (8 A rated, C-curve).
Breaking capacity and selectivity
This RCBO carries two breaking-capacity ratings: 4.5 kA per EN 60898 (the domestic-and-similar-installation standard) and 15 kA per IEC 60947-2 (the industrial standard). The higher IEC figure means it can be applied in commercial or light-industrial distribution boards where fault currents exceed 6 kA, as long as the upstream device coordinates. The 1 kA surge-current withstand (8/20 µs waveform) tells you it won't nuisance-trip on lightning-induced surges common in outdoor-fed panels.
Installation and wiring notes
Snaps onto DIN rail — any mounting position, 70 mm installation depth. Screw terminals accept 0.75 to 35 mm² solid or stranded copper, torqued to 2.5–3 N·m. Supply can enter from top or bottom; neutral conductor switching is built in. IP20 with the distribution board installed and conductors connected — standard for enclosed panel use, not for wet environments. Halogen-free and silicon-free construction suits clean-room or high-reliability builds where outgassing matters.