What this MCCB is and what it does
The Siemens 3VA2140-7MQ32-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed specifically for motor protection — that means its trip curve and thermal memory are tuned for motor inrush, not just feeder protection. It carries a continuous rated current of 40 A across the full ambient range from 40 °C up to 70 °C, so no derating gymnastics when the panel runs hot. The adjustable thermal overload range starts at 8 A and goes to the 40 A full-scale value, giving you a wide window to match the motor FLA without swapping breaker frames.
Interrupting capacity — what those kA numbers mean for your panel
This breaker delivers 330 kA interrupting capacity at 240 V, dropping to 242 kA at 415 V and 440 V, then 187 kA at 500 V, and 3.7 kA at 690 V. The steep drop at 690 V tells you this is a 480 V class MCCB — it will clear a fault at 690 V, but the available fault current at that voltage must be kept very low. For most 400 V class motor control centers, the 242 kA figure gives enormous headroom over typical 50-65 kA SCCR panels.
Protection and communication features
Built-in phase failure detection and a ground-fault monitoring version using summation current formation on the L-conductor mean this breaker can catch the common motor-killing events — single-phasing and ground leakage — without needing an external relay. It also carries a communication function and an 'other measurement function' capability, which suggests it can report trip data and status over a bus, though the exact protocol isn't specified here. No undervoltage release is fitted, so if you need UVR for your safety circuit, that's an accessory add-on.
Panel fit and mounting
At 105 mm wide, 181 mm tall, and 86 mm deep, this 3-pole MCCB fits standard Siemens SENTRON mounting footprints. The 86 mm depth is shallow enough for most 200 mm deep enclosures, leaving room for wiring gutters and busbars behind the breaker. No trip indicator window on the front — you'll need to read the handle position or use the communication output for status.