400 A MCCB with ETU340 — what the ratings mean for fit
The Siemens 3VA2440-7HK32-0AA0 is a SENTRON 3VA2 molded case circuit breaker rated for 400 A continuous current at 40 °C through 70 °C ambient — no derating needed across that entire temperature band, which simplifies panel design in warm enclosures or near heat sources. Breaking capacity reaches 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 9 kA at 690 V — the 240 V and 415 V figures are what matter for most North American and IEC distribution panels, respectively. The ETU340 electronic trip unit (design of the overcurrent release) provides adjustable long-time, short-time, and instantaneous protection curves, making this breaker suitable for line protection in main or feeder distribution — not a motor-protective device. Rated insulation voltage Ui is 800 V; the 3-pole form factor fits standard 3-phase buswork. Front IP40 protection keeps dust out of the trip-unit compartment in panel environments.
Sourcing and lifecycle — active, quoted to order
Maximum power loss is 63.5 W — factor that into enclosure thermal calculations, especially in multi-breaker panels.
Panel integration — physical fit
Dimensions: 248 mm height, 138 mm width, 110 mm depth — fits standard MCCB panel cutouts and bus-bar spacing for 400 A frame sizes. Operating temperature range -25 °C to 70 °C; storage range -40 °C to 80 °C. The storage minimum covers cold warehouse conditions, the operating max suits hot-aisle or outdoor cabinet deployments.