The Siemens SENTRON 5SU1353-1KL06 is a 2-module (36 mm wide) RCBO — residual current circuit breaker with overcurrent protection — combining a 6 A thermal-magnetic MCB (C-curve) and a 30 mA residual current device in one 1P+N unit. It's rated for 230/240 V AC at 50 Hz and breaks faults up to 4.5 kA per EN 60898. That 4.5 kA SCCR covers the majority of final subcircuits in residential and light commercial distribution boards; if your upstream fault current exceeds that, you'll need a current-limiting upstream MCB or fuse to keep coordination.
Thermal derating — the real current rating depends on your panel ambient
The 6 A rating is at 30 °C ambient. At 40 °C it's 5.7 A, at 50 °C it's 5.4 A, and at 60 °C it drops to 5.1 A. If your distribution board runs hot — say 55 °C internal ambient from adjacent loads — you're down to 5.22 A continuous. That matters for BOM accuracy: a 6 A RCBO on a 5.5 A continuous load in a 50 °C panel is already at 100% utilization. Leave headroom or step up one frame size.
Mounting and integration — DIN rail, any position, top or bottom feed
Snaps onto 35 mm DIN rail, occupies 2 width units (36 mm), with 70 mm installation depth behind the panel. The supply can enter from either top or bottom — no mandatory orientation. Mounting position is unrestricted, so it fits in tight enclosures where you're rotating rows to save space. IP20 with conductors connected and distribution board installed; that's standard for enclosed distribution boards, not for open-panel wet areas.