What it is and what it does
The Siemens 5SU1356-6KV13 is a combined residual-current device and miniature circuit breaker (RCBO) — an FI/LS protector — in a single 1+N-pole module. It integrates Type A residual current detection (sensitive to pulsating DC and AC fault currents) with a 6 kA breaking capacity and a B-curve overcurrent trip at 13 A. The 30 mA rated residual operating current (IΔn) provides personal protection against direct contact in TN and TT systems.
What the ratings mean for fit
The B-curve trip characteristic (13 A rated current) means the magnetic release operates between 3 and 5 times In — so it clears short-circuits quickly but tolerates the inrush of resistive and moderate motor loads. The 6 kA breaking capacity (Icn) is the short-circuit withstand rating per EN 60898; it safely interrupts faults up to 6 kA without welding the contacts. The 30 mA Type A RCD function covers sinusoidal AC and pulsating DC fault currents — the standard requirement for socket-outlet circuits and most commercial final circuits. The 1+N-pole form factor (switched phase, switched neutral) occupies a single modular DIN-rail width, so it replaces a separate MCB + RCD pair in the same panel space.