What this breaker is and what the ratings mean
The Siemens 3VA2463-5HN42-0BH0 is a 4-pole IEC frame 630 circuit breaker with an ETU350 LSI trip unit, rated In=630 A. The Icu of 55 kA at 415 V AC means it can safely interrupt a fault current up to that level without failing — critical for selectivity coordination in a distribution panel where the upstream transformer or bus can deliver that kind of energy. The LSI trip (Long-time, Short-time, Instantaneous) gives you adjustable overload (Ir from 250 A to 630 A), short-time pickup (Isd from 1.5 to 9x Ir), and a fixed instantaneous pickup at 9x In (5670 A). That lets you dial in coordination with downstream feeders without oversizing the breaker.
Where it fits in the panel
This breaker mounts on a DIN rail or directly on a mounting plate in a standard IEC distribution panel. The 4-pole configuration handles three-phase plus neutral, and the neutral protection is adjustable — OFF, 50%, or 100% of the phase rating — which matters for 4-wire systems where the neutral may carry harmonic currents. The built-in undervoltage release (24 V DC) lets a safety circuit or emergency-stop chain drop the breaker without a separate shunt-trip module. Two auxiliary switch channels are available for status feedback to a PLC or SCADA.