What this MCCB carries — and where it fits
The Siemens SENTRON 3VA2340-5JQ42-0DC0 is a 4-pole molded case circuit breaker (MCCB) rated 400 A continuous at 40 °C, sized for line-protection duty in distribution panels. Its interrupting capacity hits 187 kA at 240 V and 121 kA at 415/440 V — enough to ride through high-fault scenarios without cascading upstream. The 4-pole construction covers three-phase-plus-neutral or dual-feed configurations common in North American and European switchgear.
Ratings that decide the fit
Full rated current holds at 400 A up to 50 °C ambient, then derates linearly to 300 A at 70 °C. That means a panel at 55 °C still carries 375 A — useful for crowded enclosures without upsizing the frame. The minimum interrupting rating is 600 A, so the breaker clears low-magnitude faults reliably, not just bolted shorts. Interrupting capacity drops sharply above 500 V — 75.6 kA at 500 V, then 7.5 kA at 690 V. For 690 V lineups, verify the available fault current stays under that threshold; otherwise step to a higher-rated frame. The 187 kA at 240 V suits large secondary transformers or bus-riser protection where fault levels are high. Max power loss is 98.5 W per pole.
Built-in communication and auxiliary hardware
This variant includes a communication function and two HQ auxiliary switches for status feedback. The undervoltage release is installed from the factory. The basic switch variant is 3VA2340-5JQ42-0AA0, which lacks the UVR and communication module.