What this MCCB delivers at the panel
The Siemens SENTRON 3VA2340-5HL42-0DH0 is a 4-pole molded case circuit breaker rated for 400 A continuous at 40 °C, sized for line protection in distribution panels. Its breaking capacity reaches 187 kA at 240 VAC and 121 kA at 415/440 VAC, giving headroom for high-fault installations like transformer secondaries or large motor control centers. The 4-pole construction handles three-phase plus neutral, common in North American and IEC 60947-2 distribution.
Thermal derating and real-world current
The 400 A rating holds up to 50 °C ambient; above that it derates linearly to 340 A at 70 °C. If your panel runs hot — say, a packed enclosure near a furnace line or solar combiner — use the 55 °C figure (385 A) or 60 °C (370 A) for sizing. The breaker dissipates up to 98.5 W at full load, so ventilation or spacing matters in a sealed cabinet.
Auxiliaries and releases built in
This variant ships with an undervoltage release (UVR) and a complement of two auxiliary switches plus one trip alarm switch (HQ). The UVR ensures the breaker trips on loss of control voltage — standard for safety circuits or emergency-stop chains. The auxiliary contacts can feed status back to a PLC or annunciator panel without adding external relays.