What this MCCB is and what it does
The Siemens SENTRON 3VA2340-7HL32-0KL0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current at 40 °C, with an adjustable thermal-magnetic trip unit covering 600 A to 4 000 A. It is designed for line protection in distribution panels and switchgear, where the high interrupting capacity — 330 kA at 240 V, 242 kA at 415/440 V, 187 kA at 500 V, and 7.5 kA at 690 V — allows it to be installed upstream in high-fault locations without cascading failure.
Ratings that decide the fit
The 400 A continuous rating holds flat from 40 °C through 50 °C, then derates linearly: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If your panel ambient runs above 50 °C, the actual ampacity is the derated value, not the nameplate 400 A. The adjustable trip range (600 A minimum to 4 000 A maximum) covers a wide band of load sizes, but the breaker's own frame and continuous rating set the practical ceiling — you cannot continuously load it past 400 A regardless of the trip setting. The high-end trip adjustment is for short-circuit and instantaneous protection coordination, not for increasing the continuous ampacity. Breaking capacity varies sharply with system voltage. At 240 V it handles 330 kA — enough for most transformer-secondaries. At 690 V it drops to 7.5 kA, so verify the available fault current at your service voltage before committing this breaker to a 690 V bus.
Built-in auxiliaries and releases
This variant ships with a shunt trip release (STL) and a full auxiliary switch complement: 2 auxiliary switches, 1 trip alarm switch, and 1 electrical alarm switch (HQ configuration). The trip indicator and voltage trigger are present; undervoltage release is not included. No ground-fault monitoring or communication function on this order code.
Physical footprint and integration
Dimensions are 248 mm high, 138 mm wide, 110 mm deep. The 138 mm width is standard for a 3-pole MCCB in this frame size — it fits existing SENTRON mounting footprints and busbar centers without re-drilling. Depth of 110 mm leaves room for rear-connected busbars in a typical 600 mm deep enclosure.