What it is and what it does
The Siemens 5SU1356-0KV13 is a combined residual-current device and miniature circuit breaker — an FI/LS protector — in a single 1+N-pole module. It integrates Type AC (WS) earth-leakage detection with a B-curve overcurrent trip, rated at IΔn 30 mA sensitivity and 6 kA breaking capacity. The 13 A B-curve characteristic handles general-purpose resistive and light inductive loads in final subcircuits, while the 30 mA RCD element protects against direct-contact faults in standard AC installations. This unit occupies a 70 mm deep DIN-rail footprint, matching the 1+N modular width for panel integration.
What the ratings mean for fit
The 30 mA IΔn is the standard threshold for personal shock protection in residential and light commercial circuits — it will trip within 300 ms at rated residual current, meeting IEC 61008 / 61009 requirements for supplementary protection. The 6 kA breaking capacity (Icn) means the device can safely interrupt a short-circuit fault up to 6 kA at its rated voltage; this suits it for downstream sub-distribution boards where the prospective fault current is below that level. The B-curve (3–5 In magnetic trip) is the default for general-purpose socket outlets and lighting circuits where inrush is modest. The 1+N-pole format switches the line conductor and disconnects the neutral; it does not provide overcurrent protection on the neutral. The 70 mm depth is standard for Siemens 5SU series RCBOs, fitting common distribution boards without crowding gland plates.