What it is and what it does
The Siemens 5SU1354-0LB32 is a 2-pole RCBO (residual current circuit breaker with overcurrent protection) from the SENTRON 5SU1 series. It combines a 32 A MCB with B tripping characteristic and a 10 kA rated short-circuit breaking capacity (acc. to EN 60898) with an AC-type residual current device in a single 36 mm wide, 2-module unit. The 1P+N configuration means it switches the live conductor and monitors the neutral for earth leakage, while the neutral is not switched.
What the ratings mean for your panel
The 32 A rating is the continuous current at 30 °C ambient; above that, the device derates linearly — 30.4 A at 40 °C, 28.8 A at 50 °C, and 24.64 A at 70 °C. If your enclosure runs hot, size the upstream protection for the derated value, not the 30 °C headline. The B characteristic trips at 3–5× In (96–160 A magnetic), which is standard for resistive and general-purpose loads where no high inrush is expected. At 36 mm wide (2 width units) and 77 mm deep, with a 70 mm installation depth, it fits standard DIN-rail distribution boards. The IP20 rating applies once the board is installed with conductors connected — not for wet or dusty environments. Mounting position is unrestricted, and the supply can enter from either top or bottom, which simplifies wiring in tight enclosures. Terminals accept solid or stranded conductors from 0.75 mm² up to 35 mm², covering most downstream circuit sizes. The device is halogen-free and silicon-free, which matters for panels in critical infrastructure or environments where outgassing must be minimized.
Compliance and approvals
Rated for overvoltage category III and energy limiting class 3, this RCBO meets the requirements of EN 60898 for the 10 kA breaking capacity. The product designation follows DIN EN 61346-2 and DIN EN 81346-2 letter code F. Ambient operating range is -25 °C to +55 °C, with storage from -40 °C to +75 °C. Maximum power dissipation is 11.4 W.