630 A MCCB with ETU350 — what the ratings mean for your panel
The Siemens SENTRON 3VA2463-6HN32-0AH0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current Iu of 630 A at 40 °C. That 630 A figure is the baseline — the breaker's thermal-magnetic or electronic trip curve is set for that nominal, but the actual ampacity derates as ambient climbs: 612 A at 45 °C, 593 A at 50 °C, all the way down to 520 A at 70 °C. For a panel sitting at 50 °C, you're limited to 593 A continuous; plan the load schedule against the derated number, not the 40 °C sticker. Breaking capacity is where this unit separates from a standard 50 kA MCCB. At 240 V it clears 242 kA; at 415 V and 440 V it holds 187 kA; at 500 V it's still 121 kA; at 690 V it drops to 40 kA. Those numbers mean it handles high-fault-current scenarios — think large transformer secondaries, busway feeds, or industrial mains where the available fault current exceeds 100 kA. The 800 V rated insulation voltage (Ui) confirms it's built for 690 V systems with margin. The ETU350 electronic trip unit is the brains — it's a microprocessor-based release with adjustable long-time, short-time, and instantaneous protection bands, plus ground-fault capability is absent on this variant (no ground fault monitoring fitted). The auxiliary contact configuration ships as 2 auxiliary switches plus 1 trip alarm switch (HQ type), giving a dry-contact status for PLC or SCADA monitoring. Latching endurance is rated at 15 000 cycles — sufficient for main feeder duty where the breaker operates infrequently, not for frequent switching.
Panel fit and integration notes
Dimensions are 248 mm high, 138 mm wide, 110 mm deep. The 138 mm width is the standard 3-pole MCCB footprint for this class — it fits the SENTRON mounting base and busbar system without adapters. Front protection is IP40, meaning it's protected against tools and wires >1 mm but not against water ingress; keep it inside a rated enclosure. The operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss is 162 W — account for that heat in the enclosure thermal calculation, especially if the panel is densely packed.