Integrator note — RCD fit and ratings
The Siemens SENTRON 5SM2636-6 is a 3-pole residual current device (RCD) rated 63 A at AC, with a 300 mA trip threshold and Type A waveform sensitivity — meaning it detects pulsating DC fault currents on top of sinusoidal AC, which covers most modern electronic loads (VFDs, switched-mode supplies, lighting ballasts) that generate half-wave rectified leakage. The unit is instantaneous (no time delay), so it trips within a cycle on a fault — suitable for circuits where nuisance tripping from inrush or surge is not expected, or where rapid disconnection is required for personnel protection (though 300 mA is above the 30 mA threshold for direct-contact protection; this is typically used for fire prevention or equipment protection on distribution sub-mains). Rated insulation voltage (Ui) is 460 V AC, overvoltage category III, pollution degree 2 — standard for fixed-installation distribution boards in commercial or industrial buildings. Operating frequency is 50 Hz only.
Temperature derating — what the 63 A means in a warm panel
The 63 A rating holds at 40 °C ambient; above that, the continuous current must be derated per the manufacturer's table: 58.6 A at 40 °C (already the reference), 56.7 A at 50 °C, 53.55 A at 60 °C, and 50.4 A at 70 °C. In a sealed distribution board with multiple devices side by side, the internal ambient can easily hit 50–60 °C, so the effective capacity is closer to 54–57 A — plan the upstream breaker accordingly. The device occupies 3 modular width units (each 18 mm, so 54 mm of DIN rail) and mounts in any position. Depth is 70 mm, which fits standard 85 mm deep enclosures with room for wiring. IP20 with connected conductors — the terminals are finger-safe only when wired; the unit is not sealed against dust ingress beyond the panel enclosure.