What this 1000 A MCCB means on the line
The Siemens 3VA2510-5HN42-0AH0 is a SENTRON 4-pole molded case circuit breaker rated for 1000 A continuous current (Iu) — that's the full-load current it can carry without tripping, up to 55 °C ambient. Above that, it derates: still 1000 A at 55 °C, then 955 A at 60 °C, 885 A at 65 °C, and 815 A at 70 °C (–). The interrupting capacity is the headline here: 187 kA at 240 V, 121 kA at 415 V, and 53 kA at 690 V (–). Those numbers mean it can safely clear a massive fault — think a bolted short on a 2000 kVA transformer secondary — without blowing apart or welding contacts. The ETU350 electronic trip unit gives you adjustable long-time, short-time, instantaneous, and ground-fault protection curves, plus an adjustable N-conductor protection (OFF, 50%, or 100%). That matters when you're feeding a panel with a shared neutral or a harmonic-rich load. The auxiliary contacts are 2 auxiliary switches plus 1 trip-alarm switch (HQ version), so you can wire status back to a PLC without an add-on module. The breaker is 280 mm wide, 320 mm tall, and 120 mm deep (–). That's a big frame — plan for a 280 mm cutout in your panel, and make sure the enclosure depth clears the 120 mm plus wiring space. Front protection is IP40, so it's fine for a dry indoor panel; no washdown rating here.
What the ETU350 trip unit gives you
The ETU350 is an electronic trip unit with a full set of adjustable protection functions: L (long-time), S (short-time), I (instantaneous), and G (ground-fault). The N-conductor protection can be set to OFF, 50%, or 100% of the phase current — critical when you're feeding a load that draws neutral current from non-linear loads like VFDs or UPS systems. The breaker also has a trip indicator so you can see at a glance if it opened on a fault, which saves time during troubleshooting.
Panel fit and wiring
Mounts in a standard panel on a mounting plate — no DIN rail for this frame size. The 280 mm width means you need to leave that much horizontal space plus clearance for arc chutes and cable bending radius. Rated insulation voltage is 800 V, so it's good for 480 V and 600 V class systems with margin. Maximum power loss is 123 W — that heat has to go somewhere, so don't bury it in a sealed box without ventilation or a derating calculation. Operating temperature range is -25 °C to 70 °C (–); storage from -40 °C to 80 °C (–).