630 A MCCB with 187 kA interrupting capacity — what that means for your main feeder
The Siemens 3VA2463-5HN32-0HK0 is a 3-pole SENTRON molded case circuit breaker rated 630 A at 40 °C ambient, with the ETU350 electronic trip unit. That 630 A is the continuous current it carries without tripping in a 40 °C panel — a standard main-switch or large-feeder rating. The real headline is the interrupting capacity: 187 kA at 240 V AC, tapering to 121 kA at 415/440 V, 75.6 kA at 500 V, and 9 kA at 690 V. Those numbers define where this breaker can be installed on the utility side of a facility — a 187 kA SCCR at 240 V means it safely clears a bolted fault at that level without rupturing, which is typical for large transformer secondaries or high-capacity busway feeds.
ETU350 electronic trip — selectivity and coordination flexibility
The ETU350 is an electronic trip unit with adjustable long-time, short-time, instantaneous, and ground-fault protection bands. That matters for coordination: you can set the short-time delay to ride through downstream faults, keeping this breaker closed while a branch breaker clears a bolted fault. The trip indicator and electrical alarm switch provide status for a PLC or annunciator panel. The shunt trip release allows remote tripping via an emergency-stop circuit or undervoltage relay — wired separately from the main load path.
Current derating across ambient temperature
The 630 A rating holds at 40 °C. At elevated panel temperatures the breaker derates: 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 switchgear enclosure runs hot — common in compact MCCs or outdoor cabinets in direct sun — use the 50 °C or 60 °C figure for your continuous load calculation. The operating ambient range is -25 °C to 70 °C, storage from -40 °C to 80 °C.
Panel integration and auxiliary wiring
Dimensions: 248 mm tall, 138 mm wide, 110 mm deep (–, –). Mounts on a standard DIN rail or direct panel via the rear slots. The front face carries IP40 protection — rated against solid objects over 1 mm, not water ingress, so keep it inside a closed enclosure. The auxiliary switch complement includes one auxiliary switch, one trip alarm switch, and one electrical alarm switch — all factory-fitted, wired to the terminal block on the front face. The shunt trip release (STL) is wired separately; verify polarity on DC control circuits to avoid coil damage.