What it is and what it does
The Siemens SENTRON 3VA2340-5HN42-0JA0 is a 4-pole molded case circuit breaker (MCCB) rated for 400 A continuous current, designed for line protection in industrial power distribution. It carries a shunt trip release (STL) for remote tripping — useful when you need to kill the feed from a safety circuit or emergency stop without being at the panel. On the interrupting side, this breaker delivers 187 kA at 240 V AC, drops to 121 kA at 415/440 V, and still holds 75.6 kA at 500 V — only at 690 V does it tail off to 7.5 kA. That's a lot of fault-clearing muscle for a 400 A frame; you can coordinate it downstream of a larger feeder without worrying about the breaker becoming the weak link. Temperature derating is baked in: it holds full 400 A up to 50 °C, then steps down to 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If your panel hits 60 °C near the top of a NEMA 12 enclosure, you still get 370 A — no need to oversize the frame for a hot corner.
What's on the van vs. what's in the panel
If you're looking at the 3VA1110-5EF32-0LA0 as a possible drop-in, don't assume it. That's a smaller-frame 3VA1, likely a 100 A class, while this 3VA2340 is a 400 A frame with a 4-pole footprint that measures 184 mm wide by 248 mm tall by 110 mm deep. The 3VA1 will be narrower and shallower — you'd be cutting new gland plate holes and reworking the bus bars. No shop, no crane, but you'll need a drill. The 3VA2340-5HN42-0JA0 is built on the base switch variant 3VA2340-5HN42-0AA0, so if you've got that base part on the shelf, the -0JA0 adds the shunt trip release — not a field-fit accessory, it's a factory-integrated variant. Swap the whole breaker, don't try to retrofit.
Sourcing and lifecycle reality
For compliance documentation, Siemens provides the usual package: IEC/EN 60947-2 certification, UL 489 listing for the North American market, and RoHS/REACH declarations. The 3VA series is globally harmonized, so the same order code works across IEC and UL jurisdictions — just verify the specific UL file number against your local inspector's requirements.
Panel fit and integration
At 184 mm wide, this 4-pole breaker fills a standard 600 mm wide enclosure with room for side-feed lugs and a neutral bar alongside. The 110 mm depth leaves generous wire-bending space in a 300 mm deep panel — no need to go to a 400 mm deep box just for this breaker. Power loss at full load is 96 W maximum. At 70 °C ambient, internal temperature stays within the 70 °C operating max.