400 A MCCB with ETU320 — what the ratings mean for your panel
The Siemens SENTRON 3VA2440-7HL32-0KA0 is a 3-pole molded case circuit breaker rated for 400 A continuous current (Iu) at 40 °C through 50 °C, derating to 360 A at 70 °C. That 400 A frame covers main feeders or large motor branch circuits in industrial switchgear. The ETU320 electronic trip unit provides adjustable overload and short-circuit protection — no communication function, no ground-fault monitoring, no phase-failure detection, so it is a straight line-protection breaker for standard distribution. Breaking capacity runs 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. At 415 V — common in European industrial panels — that 242 kA interrupting rating handles high-fault scenarios without cascading upstream breakers. The 800 V rated insulation voltage (Ui) confirms it is rated for 690 V line-to-line systems. This MCCB includes a shunt trip (STL) auxiliary release for remote tripping — useful for emergency-stop circuits or supervisory shutdown. The supplied basic switch carries order code 3VA2440-7HL32-0AA0, and the integrated auxiliary trip is 3VA9688-0BL33. No auxiliary contacts are fitted as standard.
Panel fit — dimensions and mounting
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep. That 138 mm width is the standard 3-pole MCCB footprint for a 400 A frame — it occupies three 45 mm-wide module positions on a DIN rail or bolts directly to a mounting plate. Panel builders should account for the 63.5 W maximum power loss when sizing enclosure ventilation.