What this RCCB is and where it fits
The Siemens SENTRON 5SV3846-8 is a 4-pole selective residual current circuit breaker (RCCB) rated for 63 A continuous at 40 °C, with a 1000 mA residual trip threshold and Type A sensitivity — meaning it detects sinusoidal AC and pulsating DC residual currents, which covers most modern electronic loads like VFDs, switched-mode supplies, and single-phase rectifiers found in control panels. Its selective (time-delayed) design means it coordinates with downstream RCCBs: under a fault, the downstream device trips first, keeping the upstream supply live for the rest of the distribution board — critical for minimizing downtime on a multi-circuit panel serving a production line or warehouse aisle. Rated for 230/400 V AC at 50/60 Hz with a 10 kA short-circuit current rating (SCCR) per IEC 61008-1, it safely interrupts faults up to that level without cascading upstream — a key coordination figure for the site electrical engineer verifying panel SCCR.
Mounting and panel integration
Snap-on DIN rail (REG) mount, 4 modular width units (72 mm wide), fits standard 35 mm DIN rail in any orientation. Depth is 70 mm; installation depth matches at 70 mm, so it sits flush with the rail edge — no overhang into the wiring channel. Supply can enter from top or bottom. IP20 rated when installed in a distribution board with conductors connected — standard for enclosed panel use, not for open washdown areas.
Thermal derating and real-world current capacity
Full 63 A rating holds from 40 °C through 65 °C ambient. At 65 °C it derates to 57.35 A, and at 70 °C to 48.8 A. The storage range is wider: -40 °C to 75 °C. Operating ambient is -25 °C to 45 °C — fine for most indoor industrial panels, but if the enclosure sits in a hot machine cell above 45 °C, the derating curve applies.