Siemens 5SU1354-0KK25 SENTRON RCBO — 25 A, 30 mA, Type B
The Siemens 5SU1354-0KK25 is a 1P+N residual current circuit breaker with overcurrent protection (RCBO) from the SENTRON family, combining a 25 A thermal-magnetic trip (Type B characteristic) with a 30 mA residual current device (Type AC) in a single 2-module-wide (36 mm) package. Temperature derating is published: at 40 °C ambient the continuous rating drops to 23.5 A, at 50 °C to 21.75 A, and at 70 °C to 18.25 A. For a panel builder loading a board near its thermal limit, this curve is the number that governs the actual circuit capacity — not the 25 A label.
The 77 mm depth (70 mm installation depth) fits standard enclosures with door-mounted equipment; the 90 mm height clears typical busbar shrouds. Supply can enter from either top or bottom, which simplifies busbar routing in a crowded board. Rated IP20 with conductors connected and the distribution board installed — standard for enclosed panel use.