The Siemens 5SU1653-6KV25 is a combined residual-current and miniature circuit breaker (FI/LS protector) in a single 70 mm-wide module, Type A (PSE/SSF) with a rated residual current IΔn of 300 mA, a short-circuit breaking capacity of 4.5 kA, and a B-curve overcurrent trip at 25 A for the 1+N-POL configuration.
The Type A (PSE/SSF) designation covers sinusoidal AC and pulsating DC residual currents, plus smooth DC up to 6 mA — the typical waveform from single-phase rectifier loads like switching power supplies or LED drivers.