What this RCBO is and what it does
The Siemens 5SU1656-0KK16 is a 2-pole (1P+N) SENTRON RCBO — a combined miniature circuit breaker and residual current device in a single 36 mm wide (2 MW) module. It protects a 230/240 V AC circuit at 50 Hz, rated 16 A at 30 °C with a B tripping characteristic, and detects AC residual currents. The B-curve means it trips between 3 and 5 times rated current — suited for resistive and general-purpose loads where inrush is modest, like lighting circuits or small control transformers. Breaking capacity is dual-rated: 6 kA per EN 60898 for domestic/commercial distribution boards, and 15 kA per IEC 60947-2 for industrial panels where fault currents run higher. That 15 kA rating gives you headroom in a sub-distribution board fed by a larger transformer — a common spec for packaging lines and conveyor systems.
Mounting and integration
Snaps onto standard 35 mm DIN rail. At 36 mm wide (2 modular units) and 77 mm deep, it leaves room for wiring in a 200 mm deep enclosure. Feed can come from top or bottom — no orientation restriction. Installation depth is 70 mm into the distribution board. IP20 rating applies once the distribution board is installed with connected conductors — standard for enclosed panel use, not for wet washdown zones.
Thermal derating — what the numbers mean
The 16 A rating is at 30 °C ambient. In a warm panel — say 50 °C — the continuous current drops to 14.4 A. At 70 °C it's 12.32 A. If you're packing this RCBO next to other heat sources in a sealed enclosure, use the 50 °C or 60 °C column for your load calculation, not the 30 °C headline number.
Lifecycle and sourcing
Construction is halogen-free and silicon-free — relevant if the panel goes into a clean-room or semiconductor-adjacent environment where outgassing matters.