Siemens 5SU1354-0LB16 — SENTRON RCBO, 2-pole 16 A Type B
The Siemens 5SU1354-0LB16 is a 2-pole RCBO (residual current circuit breaker with overcurrent protection) from the SENTRON series, combining a 16 A overcurrent trip (characteristic B) with a residual current Type AC detection circuit in a single 36 mm-wide module. It is rated for 10 kA breaking capacity per EN 60898 and 20 kA per IEC 60947-2, meaning it can safely interrupt fault currents up to those levels in a residential or commercial distribution board. The residual current element is Type AC — sensitive to sinusoidal AC fault currents only — so it is suited for general-purpose circuits with resistive or inductive loads that do not generate pulsed DC fault currents. The unit occupies 2 modular width units (36 mm) on a DIN rail, with a depth of 77 mm and an installation depth of 70 mm. Supply can be connected from either the top or bottom, which simplifies panel wiring when busbar routing dictates the feed direction. The enclosure is rated IP20 once installed in a distribution board with connected conductors — standard for indoor panel use, not for wet or dusty environments.
Temperature derating and installation constraints
The 16 A rating is valid at 30 °C ambient. At elevated panel temperatures the continuous current must be derated: 15.2 A at 40 °C, 14.4 A at 50 °C, 13.6 A at 60 °C, and 12.32 A at 70 °C. If the RCBO is mounted in a crowded enclosure or near heat-generating devices, use the 40 °C or 50 °C column as the design limit — the 30 °C figure is only safe in a well-ventilated, uncrowded board. The operating range spans -40 °C to 75 °C, so it handles outdoor enclosures in cold climates as long as the IP20 rule is respected. Mounting position is unrestricted, and the device is halogen-free and silicon-free — relevant for installations where outgassing from a fault could damage sensitive electronics or where silicone contamination must be avoided. The product carries touch protection and is rated for overvoltage category III and pollution degree 2, which covers fixed-installation distribution boards in residential and commercial buildings.