The Siemens 5SU1656-7KV32 is an FI/LS-Protector (RCBO) Type A, combining overcurrent and residual-current protection in a single 1+N-pole unit. The 70 mm width fits standard Siemens distribution board cutouts.
The 300 mA residual-current sensitivity (Type A) detects pulsating DC fault currents, which standard AC-only RCDs miss; this is required for circuits with single-phase rectifiers, switched-mode power supplies, or variable-speed drives.
Panel integration
The 70 mm module width (4.5 standard DIN modules) snaps onto a DIN rail in the distribution board. The 1+N-pole design switches the line conductor only; the neutral is switched internally for isolation but not protected against overcurrent.