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 6 kA breaking capacity at 230/400 V is sized for final subcircuits in residential and light commercial distribution boards — not for main switchboard fault levels.
What the Ratings Mean
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). The B-curve 10 A overcurrent element trips at 3 to 5 times rated current (30-50 A), which is the standard characteristic for resistive and general-purpose loads; it is not intended for motor-starting inrush (use C or D curve for that). The 6 kA breaking capacity is the maximum prospective fault current the device can safely interrupt — adequate for most final circuits downstream of a distribution board with a higher-rated upstream breaker.
Deployment Context
The 70 mm width (4 module spaces) snaps onto standard DIN rail in a consumer unit or sub-distribution board. 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.