What this 630 A MCCB means on the line
The Siemens 3VA2463-5HN32-0DA0 is a SENTRON molded case circuit breaker rated for 630 A continuous current at 40 °C, with an ETU350 overcurrent release and an integrated undervoltage release. It's a 3-pole unit built for line protection in high-current distribution — think main feeder breakers in a motor control center or a heavy industrial panel. The 187 kA breaking capacity at 240 V (121 kA at 415 V, 121 kA at 440 V, 75.6 kA at 500 V, and 17 kA at 690 V) means it can safely interrupt a fault up to those levels without the arc blowing upstream. That kind of interrupting rating is what you need when the transformer is big and the bolted-fault current is serious.
Current derating and thermal reality
The 630 A rating at 40 °C drops as the ambient climbs: 612 A at 45 °C, 593 A at 50 °C, 575 A at 55 °C, 557 A at 60 °C, 538 A at 65 °C, and 520 A at 70 °C. If your panel runs hot — and a lot of them do out here in the grease — that derating curve tells you exactly where you stand. The maximum power loss is 164.5 W, so plan for the heat dissipation in the enclosure. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Physical fit and integration notes
The breaker measures 248 mm high by 138 mm wide by 110 mm deep. It mounts on a DIN rail or bolts directly into a panel. The front face carries an IP40 rating — splash protection from the front, but keep it out of washdown zones. The undervoltage release is built in (order code 3VA9608-0BB25 for the auxiliary trip block), and there's no auxiliary contact or communication module on this variant. If you need remote status or trip indication, you'll add the auxiliary contact separately.