What this MCCB is and what it does
The Siemens SENTRON 3VA2463-6KP32-0KA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection — meaning it sits on the incoming feeder or a large subfeed, not on a motor branch. Its 630 A continuous current at 40 °C and 242 kA breaking capacity at 240 V tell you this breaker is sized for high-fault installations: main switchboards, transformer secondaries, or industrial distribution where fault currents run high. The 187 kA at 415 V and 440 V keeps it usable across common 400 V class systems in Europe and Asia. The ETU850 electronic trip unit provides adjustable protection curves, and the shunt trip (STL) release allows remote tripping — a safety requirement for emergency-stop circuits. No ground-fault monitoring or auxiliary contacts on this variant, so plan those externally if the application needs them.
Current derating and thermal limits
The 630 A rating holds only at 40 °C ambient. Above that, derate: 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 the panel ambient runs 50 °C, the breaker's usable current drops to 570 A — size the upstream transformer and bus accordingly. Operating ambient range is -25 °C to 70 °C; storage range -40 °C to 80 °C. Maximum power loss at rated current is 162 W — account for that heat in the enclosure ventilation.
Dimensions and panel fit
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep. That 110 mm depth matters for enclosure depth — standard 200 mm deep enclosures have clearance for wiring and the shunt trip wiring tray. Width of 138 mm determines the DIN-rail or mounting-plate spacing; allow at least 150 mm per breaker for adjacent units and cable bending radius.