What it is and what it does
The Siemens 5SU1354-0LB13 is a SENTRON RCBO — a combined residual-current and overcurrent protective device — in a 1P+N configuration, meaning it switches the line conductor and monitors the neutral for ground faults while providing overcurrent protection on the line side only. Rated 13 A with a B tripping characteristic (3–5 In instantaneous trip), it is sized for residential or light commercial final circuits where the load is predominantly resistive or has modest inrush, such as lighting or general-purpose socket outlets. The 10 kA breaking capacity per EN 60898 is the standard domestic-level fault-interruption rating; it safely clears a short-circuit up to that prospective current without needing an upstream current-limiting device.
Ratings that govern the fit
The 13 A rating is the continuous current at 30 °C ambient. Above that, the device derates: 12.48 A at 40 °C, 12.22 A at 45 °C, 11.96 A at 50 °C, 11.57 A at 55 °C, 11.31 A at 60 °C, 10.53 A at 65 °C, and 10.01 A at 70 °C. If the panel ambient runs warm — common in a crowded enclosure — the usable load current drops; size the downstream circuit accordingly. The B curve means the magnetic trip fires between 3 and 5 times rated current (39–65 A), fast enough for cable protection but not so sensitive that it nuisance-trips on a motor starting surge. The fault-current type is AC-only (senses sinusoidal residual currents). For pulsating DC or smooth DC fault currents, a type A or type B RCBO would be needed. Overvoltage category III means it is rated for fixed-installation downstream of the main distribution board, not for equipment-level (Cat II) or utility-metering (Cat IV) positions. Energy limiting class 3 indicates it lets through less let-through energy (I²t) than class 1 or 2 devices, reducing stress on downstream cables and components during a fault.
Panel integration and wiring
The RCBO occupies 2 width units (36 mm) on a DIN rail, with a depth of 77 mm and an installation depth of 70 mm behind the panel cover. It accepts solid or stranded conductors from 0.75 mm² up to 35 mm² — covering everything from 1.5 mm² lighting circuits to 10 mm² feeder tails. The supply can enter from either top or bottom, which simplifies busbar routing in a crowded distribution board. IP20 with the distribution board installed and conductors connected; the front face is finger-safe only when the board cover is closed. Halogen-free and silicon-free construction matters if the board is in a ventilated area where off-gassing from a fault could reach sensitive electronics or if the installation specification demands low-smoke, zero-halogen materials. Mounting position is any — the device operates correctly upright, sideways, or inverted, which helps when the DIN rail is oriented vertically.
Compliance and documentation
The RCBO is designed to EN 60898 (the European standard for circuit-breakers for overcurrent protection in household and similar installations) and carries the CE marking. The device is classified per DIN EN 61346-2 and DIN EN 81346-2 as function code F (protective device). The minimum test voltage for the integral test circuit is 195 V AC — the test button will not operate correctly below that line voltage. Ambient operating range is -25 °C to +55 °C; storage range extends from -40 °C to +75 °C.