What this MCCB is and what it protects
The Siemens 3VA1140-6EF32-0HH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection — meaning it sits at the incoming feed to protect cables and downstream distribution, not a specific motor or load. It's rated 40 A continuous at 40 °C ambient, and it holds that same 40 A rating all the way up to 50 °C, only starting to derate at 55 °C (39 A) and 65 °C (38 A). That thermal stability matters when you're packing breakers into a warm panel. Breaking capacity is where this unit earns its keep: 220 kA at 240 V, 154 kA at 415 V, 121 kA at 440 V, and still 17 kA at 690 V. Those numbers mean it can interrupt a massive fault at typical distribution voltages without the arc re-striking or the case rupturing. For a 3-pole 40 A frame, that's a high-interrupting rating — you spec this where the available fault current is high, like a main breaker in an industrial panel fed close to a transformer.
Auxiliaries and releases — what's inside the case
This variant ships with a shunt trip (STL) release and a complement of 2 auxiliary switches plus 1 trip alarm switch (HQ configuration). The shunt trip lets you remotely trip the breaker via a control signal — useful for emergency-stop circuits or interlocking with a fire-suppression panel. The auxiliary switches give you status feedback (open/closed) back to a PLC or indicator lamp; the trip alarm switch signals that the breaker tripped on fault, not manual operation. No undervoltage release on this order code, so if you need UVR for a safety circuit, you're looking at a different suffix. Rated insulation voltage is 800 V, which covers 480 V and 600 V class systems with margin. The breaker's power loss at full load is 10.8 W — negligible for panel heat calculations unless you're stacking a dozen of these in a sealed enclosure.
Panel fit — DIN rail and footprint
Dimensions are 130 mm high, 76.2 mm wide, 70 mm deep. That's a standard 3-pole MCCB footprint — it snaps onto DIN rail and occupies roughly the same slot as other SENTRON 3VA frame sizes. The 76.2 mm width (3 inches) is the critical number for multi-breaker layouts: it dictates how many poles fit across a given sub-feed section.
What the ratings mean for your panel
The 40 A rating at 40 °C is the continuous current the breaker carries without tripping. If your panel ambient runs 55 °C, you lose 1 A; at 70 °C you're down to 37 A. That's a gentle derate curve — some competitors drop harder above 40 °C. The 220 kA at 240 V is the short-circuit current rating (SCCR) for that voltage level; it tells you the breaker can safely interrupt a fault up to that magnitude. For a 40 A frame, that's a very high interrupt rating — you'd typically see this on a main breaker in a high-fault installation.