Siemens 3VA1340-5EF32-0AJ0 SENTRON MCCB, 400 A, 3-Pole

The 3VA1340-5EF32-0AJ0 is a 3-pole SENTRON molded case circuit breaker rated for 400 A continuous current (Iu) across ambient temperatures up to 50 °C before derating begins — at 55 °C it still carries 392 A, at 70 °C it holds 367 A (–). That thermal curve means this breaker fits a 400 A bus without oversizing for a warm enclosure, as long as the panel ambient stays under 50 °C. The TM240 overcurrent release is a thermal-magnetic unit tuned for line protection — it handles overloads and short-circuits in distribution, not motor-starting duty cycles. Breaking capacity is the headline number for a main breaker: 187 kA at 240 V, 121 kA at 415 V, and 11.9 kA at 690 V (–). At 415 V, that 121 kA SCCR gives headroom above typical utility fault currents in most industrial panels — you can place this upstream without worrying about series-rating limits on downstream breakers. For a main breaker feeding a PLC cabinet, that trip alarm can drive a hardwired shutdown signal without a separate monitoring relay.