What this MCCB carries — and what it doesn't
The Siemens 3VA2440-5HM42-0AA0 is a SENTRON molded case circuit breaker (MCCB) built for line protection, not motor or feeder selective coordination. Four poles, rated 400 A continuous at 40 °C through 70 °C — no derating across that band, which is unusual and means the thermal-magnetic trip assembly is oversized for the frame. Interrupting capacity hits 187 kA at 240 V, 121 kA at 415 V, and still 9 kA at 690 V, so it handles high-fault utility feeds or transformer secondaries without cascading upstream. The ground-fault monitoring uses summation current formation on L+N, so it's wired for residual sensing on the neutral path. No undervoltage release, no communication module, no trip indicator — this is a bare line-protection breaker, not a smart or selectively coordinated device.
Panel fit and mounting
Dimensions: 248 mm high, 184 mm wide, 110 mm deep. That depth is shallow enough for a 200 mm deep enclosure with gland-plate clearance. Four-pole frame means it occupies the full width of a standard 600 mm wide panel's backplate if you leave side wiring gutters. No DIN-rail mount — this is a bolted-frame MCCB; plan for busbar or cable lugs on the line and load side. Maximum power loss is 63.5 W, so account for that in the thermal budget if you're stacking breakers in a sealed enclosure.
What the interrupting ratings mean for coordination
The 187 kA at 240 V is the short-circuit current rating (SCCR) at that voltage — it means the breaker can safely interrupt a fault up to that level without welding contacts or rupturing the case. At 415 V it's 121 kA, at 500 V it's 75.6 kA, at 690 V it drops to 9 kA. If your transformer secondary or generator bus can deliver more than 9 kA at 690 V, this breaker is not the right choice for that voltage level. The 400 A continuous rating is flat across 40 °C to 70 °C ambient, so no derating curve to calculate for warm enclosures.