The Siemens 5SV3646-3 is a 4-pole residual current circuit breaker (RCCB) from the SENTRON family, Type F, short-time delayed, rated 63 A with a 300 mA residual operating current for 400 V AC systems at 50/60 Hz. The short-time delay (Type F) means it tolerates brief high-frequency leakage pulses from variable-speed drives or UPS equipment without nuisance tripping — a common need on modern lines with VFD-fed motors.
Snaps onto DIN rail (REG) — standard 35 mm profile. Depth is 70 mm, same as the installation depth, so it sits flush with the front edge of a standard distribution board. The IP20 rating applies once the distribution board is installed with conductors connected; that's typical for enclosed panel gear, not for open-chassis use.
The 300 mA residual sensitivity is a higher threshold than the standard 30 mA, chosen for equipment protection or where leakage from drives would trip a more sensitive unit. The short-time delay (Type F per IEC 61008-1) gives it a 0.8 kA rated conditional short-circuit current according to that standard, and the 10 kA SCCR covers the fault-clearing capability per IEC 60947-2.