What it is and what it does
The Siemens 5SM1356-6 is a SENTRON residual-current circuit breaker (RCCB) — a 4-pole, Type A device rated for 63 A at 500 V AC, with a 30 mA trip threshold. Type A means it detects sinusoidal AC residual currents plus pulsed DC residual currents up to 6 mA, covering the bulk of modern electronic loads (switched-mode supplies, variable-speed drives, rectifiers) that a plain AC-sensitive RCCB would miss. The instantaneous design (no short-time delay,) means it trips within the standard RCCB response window — no intentional delay for coordination with surge arrestors or downstream devices.
Key ratings and what they mean for fit
The 63 A continuous rating holds at 40 °C and 45 °C without derating; at 50 °C it drops to 60.48 A, at 55 °C to 57.96 A, and at 60 °C to 55.44 A (–). If the panel ambient inside the enclosure runs above 45 °C, size the upstream overcurrent device accordingly — the RCCB itself is not a current-limiting device and relies on an MCB or fuse for overcurrent protection. The 10 kA short-circuit current rating is the withstand capacity; downstream coordination per EN 60898 yields 0.8 kA, and per IEC 61008-1 also 0.8 kA. In practice, if the prospective fault current at the installation point exceeds 0.8 kA, an upstream MCB with sufficient breaking capacity must clear the fault before the RCCB sees damaging let-through energy.
Installation and integration
Snap-on DIN rail mounting in any orientation. Occupies 4 modular width units. Installation depth is 55 mm. Supply can enter from top or bottom. IP20 with connected conductors and distribution board installed. Finger and back-of-hand safe touch protection. Silicon-free construction.