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 70 mm module width (4.5 TE on a standard DIN rail) and 1+N-POL format make it a direct fit for residential or light commercial distribution boards where combined earth-leakage and overcurrent protection is required in a single slot. 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.