What this 630 A MCCB is and where it fits
The Siemens SENTRON 3VA2463-6JQ32-0KH0 is a 3-pole molded case circuit breaker (MCCB) rated 630 A at 40 °C, designed for line protection in distribution panels and switchgear. Its 242 kA breaking capacity at 240 V handles high-fault-current service entrances and large feeder circuits; the 187 kA rating at 415 V and 121 kA at 500 V keep it viable for industrial 400 VAC three-phase systems. The 110 mm depth x 138 mm width x 248 mm height footprint fits standard SENTRON 3VA2 panel cutouts and busbar layouts — no re-drilling if you're swapping within the series.
Thermal derating and power loss — plan the panel ventilation
The 630 A rating holds at 40 °C ambient. Above that, derate in 30 A steps per 5 °C rise: 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 enclosure hits 50 °C, you lose 60 A — factor that into the feeder load. Maximum power loss is 162 W, which drives the heat rise inside the panel; a crowded cabinet may need forced ventilation or a larger enclosure to stay under the 70 °C operating maximum.
Breaking capacity across voltage levels
This MCCB delivers 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 9 kA at 690 V. The 9 kA figure at 690 V is the low end — if your system runs 690 V with fault current above that, this breaker isn't the right choice. The adjustable trip range runs from 945 A minimum to 5,670 A maximum (1.5x to 9x the 630 A frame), with a 126 A initial value and a full-scale value of 630 A. A trip indicator and undervoltage release are built in; the auxiliary switch configuration includes 2 auxiliary switches plus 1 trip alarm switch (HQ type).