What this MCCB is and what it does
The Siemens 3VA2463-5JQ32-0AC0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It's a 3-pole unit rated 630 A at 40 °C, with an adjustable thermal-magnetic trip that ranges from 126 A to 630 A full-scale — so you set the pickup to match the downstream load, not the other way around. The 187 kA breaking capacity at 240 V tells you this breaker can interrupt a fault current that high without welding contacts or venting gas into the enclosure. At 415 V and 440 V it still holds 121 kA; at 690 V it drops to 9 kA — that's the voltage's effect on arc extinction, not a defect. For a 480 V panel, the 75.6 kA at 500 V is the relevant figure, and it's enough for most industrial service-entrance or feeder positions.
Thermal derating — don't ignore it
The 630 A rating is only valid at 40 °C ambient inside the enclosure. At 45 °C it's 600 A; at 50 °C, 570 A; at 60 °C, 510 A; at 70 °C, 450 A. If your panel runs hot — and most do, especially with multiple breakers ganged — you need to apply this derating curve or the breaker will nuisance-trip on a load it should carry. The maximum power loss is 162 W, so factor that into your enclosure ventilation calculation.
Physical fit and panel integration
The 3VA2463-5JQ32-0AC0 measures 248 mm tall, 138 mm wide, and 110 mm deep. That's a standard SENTRON 3VA form factor — it mounts on a DIN rail or bolts directly into a panel. The 110 mm depth means it clears most 200 mm deep enclosures with room for wiring gutters. Verify the cutout dimensions against your existing panel layout; the width is the critical dimension for multi-breaker rows.