The Siemens 3VA2340-7HN32-0DH0 is a SENTRON molded case circuit breaker (MCCB) rated for 400 A continuous current across its ambient temperature range up to 50 °C — no derating needed until 55 °C. It is a 3-pole unit designed for line protection, carrying a 330 kA interrupting rating at 240 V and 242 kA at 415 V, which makes it suitable for high-fault-current industrial distribution panels where selectivity with upstream gear is a requirement.
Rated for the full 400 A up to 50 °C — thermal curve matters
The breaker holds its 400 A rating from 40 °C through 50 °C. At 55 °C it derates to 385 A, and at 70 °C it delivers 340 A. For a panel running warm — say 55 °C ambient — you are still at 385 A, which is a 3.75% margin below the label. That matters if your continuous load is right at 400 A and the enclosure runs hot; you need the thermal curve for a proper coordination study.
Interrupting capacity: where the 330 kA at 240 V applies
At 240 V the breaker clears 330 kA symmetrical. At 415 V and 440 V it clears 242 kA. At 500 V it drops to 187 kA, and at 690 V it clears 7.5 kA. For a 480 V line-to-line panel (common in North America) the relevant figure is the 500 V rating — 187 kA — which still covers most utility-fault scenarios. The sharp drop at 690 V means this breaker is not the first choice for 690 V distribution unless the available fault current is known to be below 7.5 kA.
Built-in undervoltage release and auxiliary switch complement
The breaker ships with an undervoltage release (UVR) integrated — the release trips the breaker when supply voltage drops below a threshold, which is standard for motor feeder protection or emergency-off chains where a voltage-loss should open the circuit. It also carries two auxiliary switches plus one trip alarm switch (HQ), giving you status feedback for the open/closed state and a separate signal for fault tripping. That is enough for a PLC input card to distinguish between a manual-off and a trip event without extra interposing relays.
Mechanical footprint: 110 mm deep, 138 mm wide
The unit measures 110 mm deep, 138 mm wide, and 248 mm tall. The 110 mm depth is the dimension that matters for enclosure depth — most 600 mm deep enclosures leave adequate wiring space behind the breaker, but a shallow 200 mm enclosure will not clear the rear arc-chamber protrusion. The 138 mm width is standard for a 3-pole frame in this class; it fits the typical DIN-rail or mounting-plate cutout pattern used across the SENTRON 3VA platform.
Lifecycle and sourcing posture
The manufacturer lists this part as current-production (active lifecycle stage). That means it is still in the standard catalog and not subject to a last-time-buy notice. For a BOM freeze or a replacement order, the supply channel is the normal Siemens distribution network; there is no urgency to stockpile or find a second source. Availability and current pricing are confirmed at quote time against an RFQ through our sourcing desk.