What the ratings mean for fit
The Siemens SENTRON 3VM1140-4ED32-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated 40 A continuous at 40 °C, with the TM210 thermal-magnetic trip unit — fixed thermal and magnetic settings, no adjustment dial. That 40 A holds through 50 °C; at 65 °C it derates to 38 A, and at 70 °C to 37 A, so if the breaker lives in a hot panel near drives or transformers, check the ambient derate curve before sizing. The 121 kA breaking capacity at 240 V AC drops to 76 kA at 415 V, 53 kA at 440 V, and 12 kA at 500 V — that's the fault current it can safely interrupt at each voltage level without welding contacts. For a 400 V distribution board, the 76 kA figure is the one that governs SCCR coordination with upstream gear. This is a line-protection design — no undervoltage release, no ground-fault monitoring, no communication module. It's a straightforward thermal-magnetic breaker for feeder or branch circuit protection in a distribution panel. The IP40 front face keeps dust out of the enclosure front but won't tolerate washdown; mount it inside a panel, not exposed.
Panel integration and footprint
The breaker measures 76.2 mm wide, 130 mm tall, and 70 mm deep — a standard 3-pole MCCB footprint that fits most DIN-rail or panel-mount enclosures. The 70 mm depth is the body only; leave clearance for cable bending radius and the arc-chute exhaust above the line terminals. No trip indicator on the front face, so fault indication relies on downstream signaling or a visual check of handle position.