What this 400 A MCCB does on your line
The Siemens 3VA2440-7MQ32-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for continuous 400 A across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling. That means it holds its full 400 A rating in a warm panel, not just on a cool bench. Three-pole construction with motor protection design, so it's built to handle induction motor starts and overload profiles, not just resistive heater banks. Phase failure detection and ground-fault monitoring via summation current formation on the L-conductor are onboard — it catches a lost phase or a ground leak without an add-on module. Interrupting capacity hits 330 kA at 240 V, 242 kA at 415/440 V, 187 kA at 500 V, and 9 kA at 690 V. That 330 kA figure at 240 V is the headline number for high-fault panels near a transformer or large motor bank — it clears a bolted fault without the arc flash escalating upstream.
Sourcing and lifecycle — still a current-production part
This 3VA2440-7MQ32-0AA0 carries a lifecycle status of 'current', meaning Siemens still manufactures it as an active catalog item. No last-time-buy notice, no successor code to track — it's the standard offering in the 3VA2 motor-protection MCCB family. For BOM freeze or PCN-watch purposes, this is a stable line. The 3VA2 series has been the SENTRON MCCB platform for several years; no phase-out signals on this rating. Sourced and quoted to order through independent distribution — availability and current pricing confirmed at quote time.
Panel fit and integration
Dimensions: 248 mm high, 138 mm wide, 110 mm deep. That 110 mm depth is the critical number for shallow backpanel enclosures — verify your cabinet depth clears it with wiring space behind. Width of 138 mm is standard for a 400 A frame; it occupies three pole spaces on the DIN rail or mounting plate. Communication function is built in — this variant supports the 3VA2 communication module for remote trip indication and power monitoring over PROFIBUS or PROFINET, depending on the plug-in module selected separately. No separate voltage trigger or undervoltage release on this order code; those are add-on accessories. Power loss at full load is 63.5 W maximum — that's the heat to sink into the panel's thermal budget. Operating temperature range -25 °C to 70 °C; storage from -40 °C to 80 °C.
Protection settings and trip characteristics
Adjustable overload protection: initial value set at 80 A, full-scale value 400 A. That's a 5:1 adjustment range — you can dial the thermal-magnetic trip down to 80 A for a smaller motor or up to 400 A for the full frame rating. Short-time delay adjustable from 3 s minimum to 25 s maximum, giving selectivity coordination with downstream breakers. Short-circuit withstand: limited to 5 kA at 1 second — this is the short-time withstand rating for selective coordination. No trip indicator, so remote signaling requires the communication module or auxiliary contacts.