What this MCCB carries — and what it means on the panel
The Siemens 3VA1110-3EF32-0KH0 is a SENTRON molded case circuit breaker (MCCB) built for line protection in distribution panels. It's a 3-pole unit rated 100 A at 40 °C, with a breaking capacity of 75.6 kA at 240 V — meaning it can safely interrupt a fault current up to that level without welding its contacts or cascading upstream. That's the figure that decides if this breaker holds downstream of a transformer or a high-capacity bus. The frame is 70 mm deep, 76.2 mm wide, and 130 mm tall — a standard footprint for the 3VA1 series, so it drops into existing SENTRON panel layouts without re-drilling gland plates. Power loss maxes at 25 W, which keeps the heat inside the enclosure manageable for a 100 A frame. It ships with a shunt trip release (STL) and a 2-auxiliary-switch + 1-trip-alarm-switch HQ configuration already fitted. That means you can remotely trip the breaker via a control signal and get status feedback — common for emergency-stop circuits or remote disconnect in automated lines. No undervoltage release on this variant, so if you need UVR for a machine-safety loop, that's a different order code.
Thermal derating — the real current you can pull
The 100 A rating holds flat from 40 °C up to 50 °C. Above that, it starts to taper: 98 A at 55 °C, 96 A at 60 °C, 94 A at 65 °C, and 91 A at 70 °C. If this breaker lives in a hot panel next to a transformer or drives, that 91 A at 70 °C is the number to BOM against — not the 100 A sticker. The operating range goes from -25 °C to 70 °C, with storage from -40 °C to 80 °C.
Breaking capacity across voltage — not just one number
The interrupting rating drops as line voltage rises: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V. If your panel feeds a 480 V bus, the 32 kA figure at 440 V is the one that matters — make sure your available fault current stays under that. The rated insulation voltage is 800 V, so the frame itself is good for higher-voltage systems even if the breaking numbers compress.