The Siemens 5SU1656-6KV10 is an FI/LS protector (RCBO) combining residual current and overcurrent protection in a single 1+N-pole module. Type A sensitivity detects pulsating DC fault currents up to 300 mA, while the B-curve 10 A thermal-magnetic trip handles short-circuit and overload.
The 300 mA residual rating is the threshold for Type A earth-leakage detection — it will trip on sinusoidal AC faults and on pulsating DC faults (typical of half-wave rectified loads like switching power supplies or LED drivers).
Deployment Context
The 1+N-pole configuration switches the line conductor only; the neutral is switched internally for isolation but not protected against overcurrent. This is the typical arrangement for single-phase final circuits where the neutral is solidly bonded upstream.