What this RCCB is and what it does
The Siemens 5SV5646-0 is a 4-pole residual current operated circuit breaker (RCCB) from the SENTRON family, rated 63 A at 230/400 V AC, 50 Hz, with a 300 mA trip threshold and Type AC sensitivity. It is designed for DIN-rail mounting in distribution boards, occupying 4 modular width units (72 mm). The 6 kA short-circuit current rating (SCCR) per IEC 61008-1 means it can safely interrupt a fault up to that level without upstream damage — a key coordination figure when you're stacking breakers downstream. The IP20 rating applies once installed in a distribution board with conductors connected; the housing itself is not rated for wet or dusty environments.
Fit and mounting
Snaps onto standard 35 mm DIN rail (REG). Depth is 70 mm, width 72 mm (4 MW), height 90 mm. Mounting position is any orientation — no derating needed for horizontal or inverted placement. Supply can enter from top or bottom. Installation depth matches the 70 mm body depth; no extra clearance needed behind the rail. The silicon-free construction matters if this goes into a paint shop or potting line where silicone outgassing causes adhesion failures.
Key ratings and what they mean for the panel
The 63 A rating is at 40 °C ambient; the thermal power dissipation per pole is 3.9 W in hot operating state — factor that into enclosure heat rise if you're packing 4+ units side by side. The 300 mA trip threshold is Type AC (sinusoidal AC residual currents only), not suitable for pulsed DC or smoothed DC fault currents — if your load includes VFDs, UPS, or rectifiers, you need Type A or B. The 6 kA SCCR is the conditional rating per IEC 61008-1 at 0.8 kA let-through; the maximum permissible series fuse is 80 A. The I²t let-through is 110 000 A²·s, and the peak let-through current is 7 100 A — these matter for selectivity coordination with upstream MCBs. Operating temperature range is -25 °C to 45 °C; storage range extends to -40 °C to 75 °C. Mechanical life is 2 000 operating cycles typical — adequate for a distribution board, not for frequent switching duty.