63 A D-curve MCB for high-inrush loads
The Siemens 5SL4163-8CC is a 1-pole miniature circuit breaker rated 63 A with a D tripping curve, breaking 10 kA at 230/400 V. The D-curve means it tolerates the high inrush currents typical of motor starters, transformers, and discharge lighting — it won't nuisance-trip on the initial surge. For a 63 A frame, that 10 kA SCCR covers most commercial and light industrial panelboards fed from a standard distribution transformer.
Active, no end-of-life worry
Lifecycle status is Active per Siemens — no PCN, no phase-out date on this code. That means it's still a standard catalog item, specifiable into new designs without a last-time-buy clock. RoHS-compliant since June 2013, with REACH Article 33 disclosure for lead above 0.1% (CAS 7439-92-1) in the current candidate list.
What the 10 kA rating means on the van
10 kA at 400 V is the standard interrupting rating for a residential or light-commercial panel main — it'll clear a bolted fault on a 63 A circuit without welding its contacts shut. If your service entrance has a higher available fault current (say 18 kA or 25 kA upstream), you'd need a current-limiting upstream breaker or a higher-rated MCB. For branch circuits downstream of a 10 kA-rated main, this fits without derating.