630 A MCCB with 242 kA interrupting capacity — what that means for your main feeder
The Siemens SENTRON 3VA2463-6JQ32-0BC0 is a 3-pole molded case circuit breaker rated for 630 A continuous at 40 °C — that's the full-load current it can carry in a 40 °C ambient without derating. At 240 V it interrupts 242 kA, at 415 V it still holds 187 kA, and at 690 V it's rated 40 kA. Those numbers tell you this breaker is sized for the main feeder or high-fault bus in a large industrial panel, not a branch circuit. The interrupting ratings cover the full voltage range from 240 V to 690 V AC, so it handles both low-voltage distribution and 400 V-class motor control centers. The 630 A frame leaves headroom for load growth on a 400 A or 500 A feeder without swapping the breaker.
Thermal derating and panel integration
The continuous rating drops as ambient rises: 630 A at 40 °C, 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 this breaker sits in a sealed enclosure with other heat sources, use the 50 °C or 60 °C column — the 164.5 W max power loss adds heat that must be ventilated. Dimensions are 248 mm high, 138 mm wide, 110 mm deep — fits standard MCCB mounting footprints in switchgear. The 15 000 mechanical endurance cycles suit it for infrequent switching (main disconnect duty), not daily motor starting.
Trip unit and auxiliary functions
The ETU560 electronic trip unit provides adjustable LSI protection (long-time, short-time, instantaneous) with communication capability — the breaker reports status and trip data over the bus. It includes an undervoltage release (UVR) that trips the breaker when control voltage drops, standard for emergency-stop or undervoltage protection schemes. Two HQ auxiliary switches (form C) are built in for remote status indication. The breaker also supports summation current ground-fault monitoring via the L-conductor method, though it does not include a separate phase-failure detection module.