630 A MCCB with ETU860 — selectivity and coordination
The Siemens SENTRON 3VA2463-5KQ32-0KL0 is a 3-pole molded case circuit breaker rated for 630 A continuous current at 40 °C, with an ETU860 electronic trip unit. That 630 A figure is the thermal baseline at 40 °C ambient; the breaker derates to 450 A at 70 °C, so the actual trip threshold shifts with panel temperature — factor that into your enclosure sizing. Breaking capacity runs 187 kA at 240 V, 121 kA at 415 V, and 55 kA at 440 V, which gives selectivity headroom for most distribution and motor feeder applications. The ETU860 release offers adjustable long-time (tr 0.5–12 s) and short-time (tsd up to 0.5 s) response values, letting you coordinate with downstream devices without sacrificing fault clearance speed.
Power loss and thermal management
Maximum power loss is 162 W at rated current. That's the heat the breaker dumps into the enclosure — for a 630 A device, it's moderate but not trivial. In a sealed panel with multiple breakers, the cumulative dissipation can push ambient above the 40 °C baseline, so check the derating curve (450 A at 70 °C) if the enclosure runs hot. The IP40 front protection means the breaker face is splash-resistant but not sealed; install it in a clean, dry electrical room or behind a panel door.
Mechanical endurance and storage
Rated for 15,000 mechanical operations — that's a standard endurance for a frame this size, fine for infrequent switching (fault isolation, maintenance disconnects). Not intended for daily load-break duty; use a contactor for that. Storage range spans -40 °C to 80 °C, so it handles warehouse extremes without issue. Operating range is -25 °C to 70 °C, covering most indoor industrial environments.
Communication and monitoring
The breaker includes a communication function and other measurement functions — the ETU860 supports optional modules for remote monitoring and trip data. Ground fault monitoring uses summation current formation on the L-conductor. No N-conductor protection on this variant; it's a 3-pole, 3-wire device for delta or solidly-grounded wye systems where neutral protection isn't required.