What this MCCB carries — and what it doesn't
The Siemens 3VA1140-3EF32-0KH0 is a SENTRON 3-pole molded case circuit breaker rated for 40 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. At 240 V it interrupts 75.6 kA; at 415 V that drops to 52.5 kA, and at 440 V it's 32 kA — numbers that tell you this is a high-interrupting-capacity unit sized for main or feeder duty in a 400 V-class panel, not a branch device. The interrupting ratings are what decide whether it coordinates with the upstream transformer or generator breaker, so check your available fault current against the 415 V column if you're on a 400 V system. It carries 2 auxiliary switches plus a separate trip alarm switch (HQ type) — that's enough for a remote status and a fault-indication signal back to a PLC or annunciator. No undervoltage release, no phase-failure detection, no communication module, no ground-fault monitoring. This is a straight line-protection MCCB: thermal-magnetic, no electronics, no fieldbus. If your BOM calls for a shunt trip for emergency-off, that's the STL release option on this unit. The TM240 release holds 40 A flat from 40 °C up through 50 °C — no derating needed in a typical ventilated enclosure. At 55 °C it's 38.4 A, at 60 °C it's 37.6 A, and it stair-steps down to 36 A at 70 °C. If your panel ambient runs hot, that derating curve is the one that governs the actual load you can hang on it.
Footprint and panel fit
The case measures 76.2 mm wide by 130 mm tall by 70 mm deep — a standard 3-pole MCCB footprint that drops into a SENTRON distribution panel or a generic DIN-rail adapter plate. The IP40 front protection means it's fine inside a closed enclosure; no washdown rating, so keep it out of wet areas. Latching endurance is rated at 15,000 operations — that's the mechanical life, not the electrical endurance under load.