630 A MCCB with ETU350 — what the ratings mean for your panel
The Siemens 3VA2463-6HN42-0AA0 is a SENTRON 3VA2 molded case circuit breaker rated for continuous 630 A at 40 °C, with a 4-pole frame and an ETU350 electronic trip unit. That 630 A is the maximum uninterrupted current it can carry in a 40 °C ambient — derate to 520 A at 70 °C if your enclosure runs hot. The interrupting ratings scale with system voltage: 242 kA at 240 V, 187 kA at 415/440 V, 121 kA at 500 V, and 9 kA at 690 V, so it handles high-fault utility feeds without cascading upstream. The ETU350 is an electronic overcurrent release with adjustable settings — not a fixed thermal-magnetic. That means you can dial in the long-time pickup, short-time delay, and instantaneous thresholds to coordinate with downstream breakers, which matters for selectivity in a distribution panel feeding motor control centers or lighting subpanels. Neutral protection is configurable: OFF, 50%, or 100% of the phase rating, set via the trip unit. The breaker ships without ground-fault monitoring, so if you need GF protection, you add an external module or specify the GF variant.
Panel integration and physical fit
The breaker measures 184 mm wide, 248 mm tall, and 110 mm deep — a 4-pole frame that occupies roughly 7.24 × 9.76 inches of panel face. IP40 on the front means it's protected against tools and wires >1 mm entering the enclosure face, but the body itself is not sealed against washdown; mount it inside a cabinet rated for the environment. Maximum power dissipation is 162 W at full rated current. That heat has to be managed inside the enclosure — factor it into your thermal budget, especially if the panel packs multiple breakers in a row with limited airflow between them.
Selectivity and coordination notes
Because the ETU350 allows adjustable short-time delay (typically 0.1–0.5 s), this breaker can be coordinated as a main or feeder device feeding downstream MCCBs or fused switches. The 242 kA SCCR at 240 V means it safely interrupts faults up to that level without upstream breakers needing to clear — critical for service-entrance applications where available fault current is high. The reference code per IEC 81346-2 is Q, confirming its function as a power circuit protection device in the functional designation system.