The Siemens SENTRON 3VM1340-5GE42-0AA0 is a 4-pole molded case circuit breaker rated for line protection, carrying 400 A continuously at 40 °C and packing a 187 kA interrupting capacity at 240 V AC. That interrupting number drops to 121 kA at 415 V and 440 V, and 76 kA at 500 V — still well above what most distribution panels upstream of a motor control center will ever see in a fault. The TM220 thermal-magnetic trip unit handles the overcurrent and short-circuit sensing inside the same can; no external relay needed.
Temperature derating and panel fit
At 55 °C the continuous rating drops to 392 A, at 60 °C it's 384 A, and at 70 °C it's 367 A. If this breaker sits in a hot enclosure next to drives or transformers, you plan the load at the ambient you'll actually see, not the 40 °C sticker. The 184 mm width and 110 mm depth mean it fits the standard SENTRON mounting footprint — same cutout as other 3VM frames in the 400 A class. IP40 on the front keeps dust out of the trip mechanism in a clean panel; no washdown rating here, so keep it inside the enclosure.
Compliance and documentation
Rated insulation voltage is 800 V, with a maximum operating voltage of 690 V AC and 500 V DC. The N-conductor protection is designed for 100% rated neutral. Storage temperature range is -40 °C to 80 °C, operating range -25 °C to 70 °C. The part carries SENTRON branding and is listed as a molded case circuit breaker under Siemens' standard compliance documentation (UL, IEC, RoHS, REACH — confirm specific certs with the factory certificate at order time).