400 A continuous, 121 kA interrupting — the MCCB for high-fault panels
The Siemens SENTRON 3VA1340-4EF42-0AA0 is a 4-pole molded case circuit breaker rated for 400 A continuous at 40 °C ambient, with a TM240 thermal-magnetic overcurrent release. Its interrupting capacity hits 121 kA at 240 V and still holds 75.6 kA at 415 V — enough to clear a major fault without cascading upstream. This is the breaker you spec when the transformer secondary or main feeder needs a clean trip curve and the panel SCCR demands real headroom.
The 400 A rating holds flat from 40 °C to 50 °C, then derates to 376 A at 65 °C and 367 A at 70 °C. The TM240 release is thermal-magnetic: thermal for overload protection with an inverse-time curve, magnetic for instantaneous short-circuit trip. No electronic adjustments, no communication module — it's a straight line-protection device for fixed-distribution applications.
The 3VA1340-4EF42-0AA0 measures 184 mm wide by 248 mm tall by 110 mm deep — a 4-pole frame that bolts into a standard switchboard or panel-mount cutout.
Compared to the smaller-frame 3VA1112-5EE32-0AA0 (a 3-pole, lower-current MCCB), the 3VA1340-4EF42-0AA0 is a physically larger 4-pole frame with a 400 A continuous rating versus the 3VA1112's lower amperage. The 3VA1112 series typically tops out around 125 A and is narrower at 105 mm wide. The 3VA1340's 184 mm width and 4-pole design mean it does not drop into a panel cutout sized for the 3VA1112 without reworking the mounting plate and bus connections. The TM240 release on this part is a thermal-magnetic design, while the 3VA1112 may carry a different release curve — verify coordination if substituting in a selective system.