What this 400 A MCCB delivers for a main feeder
The Siemens 3VA2340-6HN32-0CL0 is a 3-pole SENTRON molded case circuit breaker rated for 400 A continuous current (Iu) with an ETU350 electronic trip unit, built for line protection in distribution panels. At 240 V it interrupts 242 kA, and the rating holds at 187 kA through 415 V and 440 V, then steps to 121 kA at 500 V and 40 kA at 690 V — that kind of headroom means it handles high-fault service entrances without cascading upstream. The 400 A rating stays flat from 40 °C up to 50 °C; above that it derates linearly, hitting 340 A at 70 °C, so the thermal curve is predictable for a warm panel.
Trip unit and auxiliary complement
The ETU350 is a programmable electronic trip unit that supports LSIG (long-time, short-time, instantaneous, ground-fault) protection profiles, though this specific variant ships without a ground-fault monitoring module. It includes an undervoltage release (UVR) for coordinated shutdown sequences. The auxiliary contact block is loaded: 2 auxiliary switches, 1 trip alarm switch, and 1 electrical alarm switch (HQ type), which gives the controls engineer a clean set of status signals back to the PLC without adding a separate module.
Panel fit and environmental limits
Dimensions are 248 mm high, 138 mm wide, and 110 mm deep — it mounts on a DIN rail or directly to a backplate in a standard MCCB footprint. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C. Maximum power dissipation is 98.5 W, so factor that into your enclosure thermal budget if it's in a sealed cabinet with other high-current devices. Rated insulation voltage is 800 V, keeping it comfortable on 480/600 V systems with margin.