What this MCCB is and what it does
The Siemens SENTRON 3VA2340-6KP32-0JH0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, meaning it sits at the main distribution point or a large feeder to protect cables and busbars from overloads and short circuits. It carries a rated continuous current Iu of 400 A and an ETU850 electronic trip unit that gives you adjustable protection curves and communication capability — the breaker can talk to a higher-level control system via the integrated communication function, which is useful for remote monitoring and selective coordination studies.
Breaking capacity — what the numbers mean for your panel
This breaker delivers 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 40 kA at 690 V. Those are the maximum fault currents it can safely interrupt at each voltage level without welding contacts or rupturing the case. For a 400 A frame, 187 kA at 415 V is high-end — it gives you headroom for high-fault installations like large transformer secondaries or industrial substations where the available fault current is well above typical commercial gear. The 40 kA at 690 V matters if you are feeding a 690 V motor control center; most MCCBs in this frame size drop off faster above 500 V.
Thermal derating — the real-world current you can run
The 400 A rating holds flat from 40 °C through 50 °C ambient. Above that it derates: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. If your panel runs hot — say inside a non-air-conditioned enclosure near a furnace line — the 300 A at 70 °C figure is the one you size your load against, not the 400 A nameplate. The operating range spans -25 °C to 70 °C, with storage from -40 °C to 80 °C.
Auxiliaries and releases — what is built in and what is not
Factory-fitted: a shunt trip (STL) for remote opening, plus 2 auxiliary switches and 1 trip alarm switch (HQ configuration). The integrated auxiliary trip is order code 3VA9688-0BL32. No undervoltage release is installed, and there is no ground-fault monitoring module — if you need GF protection, you add an external module or choose a different variant. The basic switch core is 3VA2340-6KP32-0AA0, so the -0JH0 suffix adds the shunt trip and the HQ auxiliary contact block.
Physical fit and panel integration
Dimensions: 248 mm high, 138 mm wide, 110 mm deep. That 110 mm depth is the front-to-back envelope including the arc chamber — measure your enclosure depth before ordering, especially if you are retrofitting into a panel originally designed for a shallower frame. The breaker mounts via the standard SENTRON 3VA base plate; no special adapter needed for most Siemens switchboard and distribution panel layouts.