What it is and what it carries
The Siemens 3VA2340-6JQ32-0HH0 is a SENTRON 3VA2 molded case circuit breaker (MCCB) for line protection, rated 400 A continuous current Iu at 40 °C through 50 °C, with no derating in that band. The 3-pole frame carries an ETU560 electronic trip unit, a shunt trip release (STL), and a communication function — meaning it can talk to a PLC or BMS over the integrated comms module, not just trip on overcurrent. Breaking capacity hits 242 kA at 240 V AC, 187 kA at 415 V, and still holds 40 kA at 690 V, so it handles high-fault industrial feeds without cascading upstream.
Thermal derating and panel fit
Above 50 °C the continuous current steps down: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, 300 A at 70 °C. In a hot enclosure near a steel mill's radiant heat, that derating curve is what governs the real ampacity — not the nameplate 400 A. The frame dimensions are 248 mm high × 138 mm wide × 110 mm deep, which fits the standard 3VA2 panel cutout and bus-bar spacing. Maximum power loss at rated load is 96 W; factor that into the enclosure's thermal rise calculation.
Auxiliaries and release configuration
Comes with 2 auxiliary switches plus 1 trip alarm switch (HQ configuration). The shunt trip (STL) allows remote tripping from a safety PLC or E-stop circuit. No undervoltage release, no phase-failure detection on this variant — those are separate order-code options if needed. The voltage-trigger function is present, so the ETU560 can respond to undervoltage events through the trip unit logic.
Environmental range
Operating temperature spans -25 °C to 70 °C; storage range is -40 °C to 80 °C. The 80 °C storage max matters if the breaker sits in a non-climate-controlled warehouse before installation — that's the handling limit, not the running limit. Rated insulation voltage Ui is 800 V, which covers 690 V AC systems with margin.