What this MCCB is and what it carries
The Siemens 3VA2340-7HL32-0KA0 is a SENTRON 3VA2 molded case circuit breaker (MCCB) rated for 400 A continuous current (Iu) at 40 °C, configured as a 3-pole line-protection device with an ETU320 electronic overcurrent release and a factory-integrated shunt trip (STL). This is the version with the shunt trip already built in — the basic switch is order code 3VA2340-7HL32-0AA0, and the auxiliary trip module is 3VA9688-0BL33. No auxiliary contact block or undervoltage release is fitted from the factory. Rated insulation voltage Ui is 800 V, and the interrupting ratings span 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 52.5 kA at 690 V — figures that cover high-fault utility feeds and transformer secondaries without cascading upstream.
Derating and thermal budget
The 400 A rating holds flat from 40 °C through 50 °C. Above that, it derates: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If the panel ambient runs hot — say, next to a drive cabinet or in a non-conditioned enclosure — the continuous current must be adjusted against this curve. Maximum power loss is 96 W at rated load. That's the heat the enclosure must vent; factor it into the thermal calculation if the breaker is in a sealed or compact panel. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Panel fit and integration
Dimensions are 248 mm high, 138 mm wide, and 110 mm deep — a standard 3VA2 frame size that mounts on a DIN rail or direct panel surface. The 138 mm width is the 3-pole footprint; verify the existing busbar or lug spacing against that dimension before committing the panel layout. The ETU320 release is electronic, not thermal-magnetic, so it offers better accuracy and adjustable trip curves. No communication function or phase-failure detection is built into this variant.