What it is and what it does
The Siemens SENTRON 3VA2463-5JP32-0JA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying 630 A continuous current at 40 °C with an 800 V rated insulation voltage. It's the high-current backbone of a distribution panel — sized for main or large feeder protection where you need selectivity headroom downstream. Breaking capacity hits 187 kA at 240 V, 121 kA at 415/440 V, 75.6 kA at 500 V, and 17 kA at 690 V. That SCCR range means it clears a fault fast enough to keep upstream gear in service — useful when the transformer secondary is stiff and you're coordinating with smaller branch breakers. The ETU550 electronic trip unit handles the overcurrent protection curve. No undervoltage release, no ground-fault monitoring on this variant, but it does carry a shunt trip (STL) and a communication function — so it can be remotely tripped and integrated into a BMS or SCADA loop.
Sizing and thermal derating
Rated 630 A at 40 °C ambient. Derate linearly through the temperature band: 600 A at 45 °C, 570 A at 50 °C, 540 A at 55 °C, 510 A at 60 °C, 480 A at 65 °C, and 450 A at 70 °C. If your panel ambient runs hot — say a non-climate-controlled enclosure next to a furnace line — use the 60 °C or 65 °C column for your continuous load calculation. Maximum power loss is 162 W. That's the heat the breaker dumps into the enclosure at full rated current — factor it into your ventilation or forced-air cooling budget, especially if you're stacking multiple breakers in a single section. Dimensions: 248 mm high, 138 mm wide, 110 mm deep. The 110 mm depth is the key fit dimension for shallow backpanels or gland-plate clearance — it's the same envelope as the standard 3VA2 fixed-mount frame, so no surprises if you're swapping in from a 3VA2 base breaker.