630 A MCCB with ETU320 — what the ratings mean for your panel
The Siemens SENTRON 3VA2463-5HL32-0KA0 is a 3-pole molded case circuit breaker rated for 630 A continuous current (Iu) at 40 °C, with an ETU320 electronic trip unit and a built-in shunt trip release (STL). The 187 kA breaking capacity at 240 V AC means it can safely interrupt a fault current up to that level without the arc flashing over or damaging upstream gear — critical for high-fault installations like transformer secondaries or large motor control centers. At 415 V and 440 V it still holds 121 kA, dropping to 75.6 kA at 500 V and 17 kA at 690 V, so the SCCR headroom is there for most industrial distributions. The rated insulation voltage is 800 V, which covers 690 V line-to-line systems with margin. Max power loss at rated current is 162 W — factor that into enclosure ventilation if you're packing several breakers in a confined panel.
Thermal derating and operating limits
The 630 A rating is at 40 °C ambient. Derate linearly: 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 panel ambient runs hot — say near a transformer or in a NEMA 12 enclosure with solar load — size the breaker for the actual temperature, not the catalog maximum. Operating range is -25 °C to +70 °C; storage from -40 °C to +80 °C.
Trip unit and release configuration
The ETU320 is a basic electronic overcurrent release — no communication, no ground-fault monitoring, no phase-failure detection. It handles LSI (long-time, short-time, instantaneous) protection curves. The shunt trip (STL) allows remote tripping via a control voltage; the breaker ships with the shunt trip integrated (order code suffix -0KA0 indicates this). No auxiliary contacts are included — if you need status feedback, you'll add them separately. The trip indicator is not present on this variant.