What this MCCB is and what it does
The Siemens SENTRON 3VA1140-6EF32-0DH0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection in distribution panels. Its headline rating is 40 A continuous current at 40 °C, with a massive 220 kA breaking capacity at 240 VAC — that means it can safely interrupt a fault current up to 220 kA without welding its contacts or cascading the fault upstream. At 415 V it still holds 154 kA, and at 500 V and 690 V it's rated 17 kA. This is not a motor-protective breaker — its design is explicitly for line protection, meaning it guards cable and busbar feeders against short-circuit and overload. The 40 A rating holds steady up to 50 °C, then derates gently to 37 A at 70 °C, which is useful to know if your panel runs hot.
Built-in auxiliaries and release
This variant ships with an undervoltage release (UVR) fitted, plus two auxiliary switches and one trip alarm switch (HQ configuration). The UVR means the breaker trips automatically when supply voltage drops below a threshold — typical for safety circuits where a machine must stop on power loss. The auxiliary switches give remote status feedback (open/closed/tripped) to a PLC or indicator lamp. Rated insulation voltage is 800 V, so the breaker is suitable for 480/600 V class panels with headroom. Power loss at full load is 13.3 W maximum — a modest heat contribution inside the enclosure.
Mounting and integration
The breaker occupies a 76.2 mm wide by 130 mm tall by 70 mm deep footprint — standard for a 3-pole SENTRON MCCB in this frame size. It mounts to a DIN rail or directly to a backplate via the rear slots. The undervoltage release coil wiring and auxiliary switch terminals are accessible from the front; no special panel cutout needed beyond the width allowance.