What this 400 A frame MCCB is and what the ratings mean for your panel
The Siemens SENTRON 3VA2340-5JQ42-0HA0 is a 4-pole molded case circuit breaker (MCCB) on a 400 A frame, designed for line protection in distribution panels. The 400 A full-scale value is the continuous current rating at 40 °C, 45 °C, and 50 °C — it holds the full 400 A through that range without derating. Above 50 °C you step down: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C (–). That thermal curve matters if this breaker lands in a hot enclosure or near other heat sources — the 70 °C ceiling is the operating maximum, but you lose a quarter of the ampacity by then. The interrupting capacity is where this part earns its keep: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V. That 187 kA at 240 V tells you it's built for high-fault industrial services — think transformer secondaries or large motor control centers where the available fault current is serious. The adjustable trip range runs from a minimum of 600 A up to the 4 000 A maximum, with an initial setting of 80 A, so it covers a wide band of overload and short-circuit protection settings. This MCCB includes a shunt trip release (STL) and a communication function — the shunt trip lets you remotely trip the breaker via a control signal, which is standard for emergency-stop circuits or remote shutdown schemes. The communication function means it can report status or accept commands over a network, though the evidence doesn't specify which protocol. The breaker also has an undervoltage release option noted as 'No', so if you need UVR you'd look at a different suffix. Trip indicator is not fitted.
Dimensions and panel fit
The breaker measures 248 mm high, 184 mm wide, and 110 mm deep — that's 9.76 by 7.24 by 4.33 inches. It's a standard SENTRON 3VA2 form factor, so it mounts into the same Siemens panelboard and switchgear footprints as other 3VA2 frames of this size. If you're swapping out a different 400 A 4-pole MCCB, check the mounting pattern and bus connection centers against your existing panel — the 110 mm depth is shallow enough for most 600 V switchgear enclosures.
Key specs at a glance for the integrator
Power loss at rated current is 96 W maximum — that's the heat you need to vent from the enclosure. Storage temperature range is -40 °C to 80 °C; operating range is -25 °C to 70 °C. The supplied basic switch order code is 3VA2340-5JQ42-0AA0, which is the base breaker without the shunt trip — so this -0HA0 variant adds the STL. No auxiliary switch is fitted.