400 A MCCB with ETU560 — what the ratings mean for your panel
The Siemens SENTRON 3VA2340-6JQ32-0DL0 is a 3-pole molded case circuit breaker rated for 400 A continuous current (Iu) across the 40 °C to 50 °C ambient band — no derating needed in that range. Above 50 °C the curve steps down: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. That means a panel running at 40 °C ambient gets the full 400 A; if the enclosure runs hot, you lose 25 A per 5 °C rise above 50 °C. Breaking capacity is 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 40 kA at 690 V. For a 480 V distribution panel (common in North America), the 187 kA at 440 V figure is the closest published value — well above typical available fault current in most industrial switchboards. The ETU560 electronic trip unit handles the protection curve. An undervoltage release (UVR) is built in, and the auxiliary contact set includes two auxiliary switches, one trip alarm switch, and one electrical alarm switch. Communication function is present, so the breaker can report status to a higher-level control system.
Integration and mounting dimensions
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep. That 110 mm depth is the dimension that matters for enclosure depth clearance — check your gland plate or back-panel clearance before committing the cutout. The 138 mm width is the panel cutout width for a 3-pole frame; verify against your existing busbar or riser spacing.
Included releases and accessories
The base switch is order code 3VA2340-6JQ32-0AA0. The integrated auxiliary trip is 3VA9608-0BB25. The undervoltage release is designed for summation current formation on the L-conductor for ground fault monitoring. Power loss at rated current is 98.5 W maximum — factor that into your enclosure thermal budget.