400 A MCCB with ETU560 — what the ratings mean for the panel
The Siemens SENTRON 3VA2340-6JQ32-0BL0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current Iu of 400 A at 40 °C ambient. That 400 A holds flat through 50 °C — per the datasheet, it only begins to derate above 55 °C, dropping to 375 A at 55 °C, 350 A at 60 °C, and 325 A at 65 °C. For a panel that runs warm, the 400 A rating at 50 °C gives genuine headroom; you don't lose capacity until the enclosure ambient pushes past that point. The breaking capacity is the real story here: 242 kA at 240 V AC, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 7.5 kA at 690 V. At 415 V, that 187 kA sits well above typical utility fault levels for most industrial switchboards — you get selectivity headroom without needing a current-limiting fuse upstream. The 690 V figure (7.5 kA) is lower, so if your line side runs at that voltage, verify coordination with the upstream device. The electronic trip unit is an ETU560, which supports LSIG protection (long-time, short-time, instantaneous, ground-fault). Ground-fault monitoring is configured as summation current formation on the L-conductor — that means it sums the phase currents via an external core-balance transformer or internal summation, not a separate GFCI module. The auxiliary contact block carries 2 auxiliary switches, 1 trip alarm switch, and 1 electrical alarm switch HQ, giving you both status and alarm feedback for the PLC or SCADA.
Lifecycle and sourcing — active, quoted to order
Supplied basic switch variant is 3VA2340-6JQ32-0AA0; the -0BL0 suffix adds undervoltage release (UVR) and auxiliary contact configuration.
Integration — panel dimensions and wiring
Mounting dimensions: 248 mm height, 138 mm width, 110 mm depth. That 110 mm depth (4.33 in) is the body depth — it fits standard MCCB panel cutouts and busbar arrangements for the SENTRON 3VA frame size. The 138 mm width (5.43 in) is the three-pole footprint; verify the busbar center-to-center spacing matches the line and load lugs before committing the drill pattern. Rated insulation voltage is 800 V, so the breaker is rated for 690 V systems with margin. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss is 98.5 W at rated current — that heat must be considered in the enclosure thermal calculation, especially if the breaker is enclosed with other heat sources.
Compliance and approvals
Product designation is molded case circuit breaker per Siemens SENTRON branding. Compliance documentation available on request.