What it is and what it does
The Siemens SENTRON 5SU1656-7KK13 is a 2-pole RCBO (residual current circuit breaker with overcurrent protection) in a 1P+N configuration — it switches the line and monitors the neutral, but only the line pole is protected against overload and short-circuit. Rated 13 A at 30 °C with a C tripping characteristic (magnetic release between 5 and 10 times In), it handles the moderate inrush of motor starters, lighting banks, and small transformers without nuisance trips. The residual current element is Type A, meaning it detects sinusoidal AC and pulsating DC fault currents — the standard choice for circuits with single-phase rectifiers, switched-mode power supplies, or electronic loads.
Breaking capacity and selectivity
Two breaking-capacity ratings let you place this RCBO in different network positions. Per EN 60898 (domestic / light commercial) it is rated 6 kA — fine for a sub-distribution board or final circuit. Per IEC 60947-2 (industrial) it carries 15 kA, which gives headroom for a main distribution panel with a larger upstream transformer. The energy limitation class is 3, so it lets through less let-through energy than a class-1 or class-2 device, making downstream coordination easier.
Thermal derating — the real-world current
The 13 A rating holds only at 30 °C. At 40 °C it derates to 12.48 A; at 50 °C to 11.96 A; at 60 °C to 11.31 A; at 70 °C to 10.01 A. If the panel ambient runs warm — say 50 °C inside a sealed enclosure — the usable current is 11.96 A, not 13 A. The mounting position is unrestricted, and the supply feed can enter from top or bottom, which simplifies busbar routing in a crowded DIN-rail assembly.