What this RCBO carries and where it fits
The Siemens 5SU1354-4KK10 is a 1P+N residual current operated circuit breaker (RCBO) from the SENTRON Super Resistant K line, combining overcurrent and earth-fault protection in a single 2-module-width (36 mm) package. Rated 10 A at 30 °C with a C tripping characteristic, it handles the inrush of motor starters, contactor coils, and small transformers without nuisance trips on start-up. Breaking capacity is 10 kA per EN 60898 and 20 kA per IEC 60947-2 — the higher figure matters when the device sits downstream of a transformer or in an industrial panel where fault current can exceed the domestic standard. Overvoltage category III and pollution degree 2 confirm it for fixed-installation distribution boards, not plug-in portable use.
Temperature derating — the real current limit
The 10 A rating holds only at 30 °C ambient. At 40 °C it derates to 9.5 A, at 50 °C to 9 A, and at 70 °C to 8 A. If the panel runs warm — and most industrial enclosures do — size the load against the derated figure, not the label. The mounting position is unrestricted, but the IP20 rating assumes the distribution board is installed with conductors connected; open-back enclosures void that protection.
Panel fit and wiring
At 36 mm wide (2 MW) and 77 mm deep (70 mm installation depth), it occupies standard DIN-rail space — two adjacent 18 mm slots. Supply can enter from top or bottom, which simplifies busbar routing in a crowded enclosure. Halogen-free and silicon-free construction matters for clean-room or semiconductor-adjacent panels where outgassing contaminants can't be tolerated.