The Siemens 5SU9406-0KK32 is a SENTRON 5SU9-series RCD-operated circuit breaker — an RCBO — combining overcurrent protection and residual-current detection in a single 18 mm-wide module. The 1P+N design switches the phase and monitors the neutral; the neutral pole is switched but not protected, so it clears line-to-neutral faults through the phase pole only. At 32 A and a B curve (3–5× In magnetic trip), it holds takt time on general-purpose socket circuits, lighting, and small motor loads where inrush is moderate — no nuisance trips on a 7.5 kW motor start, but right for a 3 kW compressor or a bank of VFD-fed conveyors.
Rated current is 32 A at 30 °C ambient. Derate linearly above that: 30.08 A at 40 °C, 29.12 A at 45 °C, 27.84 A at 50 °C, 25.92 A at 55 °C. If the panel ambient runs 45 °C (common in a sealed enclosure near a weld line), you lose about 9 % of the rating — plan for a 29 A continuous load max. Energy limiting class 3 means it lets through less let-through energy (I²t) than a class-1 MCB — better downstream device protection.
Width is 18 mm (1 width unit). Mounting position any; installation depth 70 mm, overall depth 77 mm. IP20 with conductors connected and distribution board installed — fine inside a panel, not for wet environments. Touch protection is integral; no need for additional finger-safe shrouds on the terminals.
Rated for overvoltage category III. Halogen-free and silicon-free construction. The functional designation per DIN EN 61346-2 and DIN EN 81346-2 is F (protective device).