The Siemens SENTRON 5SU1654-1KK06 is a 2-pole RCBO combining overcurrent protection (C-curve, 6 A rated) with a 300 mA residual-current device in a single 36 mm-wide module. It's a current-production part — no lifecycle concerns for a new BOM line.
The 300 mA residual sensitivity is for equipment protection or circuits where 30 mA would cause false trips from leakage — think water heaters, pumps, or distribution subfeeds. Thermal derating is published: at 40 °C ambient the continuous rating drops to 5.7 A, at 50 °C to 5.4 A, and at 70 °C to 4.62 A.
Two modular-width units (36 mm) snap onto standard DIN rail. Depth is 77 mm (70 mm installation depth), so it fits flush in most distribution boards without a deep enclosure. Touch protection is built in — no exposed live parts when wired correctly. Rated IP20 with the distribution board installed and conductors connected — that's normal for a panel-mount device; it's not a standalone outdoor unit.
The design is instantaneous (no intentional time delay on the RCD element).