The Siemens 5SU1354-7LB16 is a SENTRON RCBO (residual current circuit breaker with overcurrent protection) in a 1P+N, 2-pole format. It carries a 16 A rated current at 30 °C with a C tripping characteristic, making it the standard choice for protecting mixed resistive and inductive loads in final subcircuits — think general-purpose socket outlets, lighting, and small appliances in commercial or residential panels. Breaking capacity is rated at 10 kA per EN 60898 and 20 kA per IEC 60947-2. The EN figure governs domestic-type installations; the IEC figure applies when the device is used in an industrial distribution board with higher prospective fault current. Either way, it clears a bolted fault up to that level without cascading upstream.
Integration & mounting
Occupies 2 modular width units (36 mm) on a DIN rail. Depth is 77 mm, installation depth 70 mm — verify the gland plate clearance if retrofitting into a shallow enclosure. IP20 rating applies when installed in a distribution board with connected conductors; the device itself is not rated for wet or dusty environments. Supply can enter from either top or bottom. Mounting position is any orientation, which simplifies panel layout. The design is short-time delayed G (residual current) and super resistant K (overcurrent) — meaning the RCD element tolerates brief surge currents without nuisance tripping, useful on circuits with electronic loads or inrush.
Thermal derating
Rated current is 16 A at 30 °C ambient. Derate linearly: 15.2 A at 40 °C, 14.88 A at 45 °C, 14.4 A at 50 °C, 13.92 A at 55 °C, 13.6 A at 60 °C, 12.96 A at 65 °C, and 12.32 A at 70 °C. If the panel internal temperature runs above 30 °C — common in a crowded enclosure — size the upstream protective device accordingly.