What this 3VA brings to the panel
The Siemens 3VA2163-8KP42-0AA0 is a SENTRON molded case circuit breaker (MCCB) with an ETU850 electronic trip unit, rated 63 A continuous across the full operating temperature range from 40 °C to 70 °C — no derating needed up to that ceiling. That flat curve is unusual for an MCCB; most thermal-magnetic units start backing off around 50 °C. Here, the electronic trip handles it, so you can load the bus to the full 63 A even in a warm cabinet. Four poles, line protection design, with communication and other measurement functions onboard — this isn't a dumb breaker. No undervoltage release fitted, no ground-fault monitoring module on this variant. Interrupting capacity is the headline: 440 kA at 240 V, 330 kA at 415/440 V, 220 kA at 500 V, and still 52.5 kA at 690 V. The 63 A continuous rating may look modest, but the interrupting rating is what buys you selectivity headroom upstream.
That 86 mm depth matters for shallow backpanels or gland-plate clearance — it's the dimension that usually bites you when swapping into an existing enclosure. Four-pole frame means it occupies the same width as a standard 4-pole MCCB; verify the bus-bar dropout spacing if retrofitting into a panel cut for a different brand.