400 A MCCB with 187 kA interrupting capacity — selectivity headroom for high-fault panels
The Siemens SENTRON 3VA2340-5HN32-0KL0 is a 3-pole molded case circuit breaker rated for 400 A continuous current at 40 °C ambient, with a maximum interrupting capacity of 187 kA at 240 V AC. That rating drops to 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 17 kA at 690 V — so the breaker's real SCCR headroom depends on the system voltage you're protecting. At 400 A continuous, the 96 W maximum power loss matters for enclosure thermal management; panel builders should account for that when sizing the gland plate and ventilation. The ETU350 electronic trip unit handles line protection with adjustable settings, and the breaker includes a shunt trip release for remote opening. Auxiliary contact configuration is 2 auxiliary switches plus 1 trip alarm switch and 1 electrical alarm switch — enough for status feedback to a PLC or SCADA system without an external interface module.
Dimensions and panel integration — fits standard 3-pole MCCB footprint
The breaker measures 248 mm high by 138 mm wide by 110 mm deep. That width is standard for a 400 A frame 3-pole MCCB; it occupies the same DIN-rail or mounting-plate footprint as other SENTRON 3VA2 frame units. The depth of 110 mm means it clears most standard enclosure depths, but verify gland-plate clearance if the breaker is mounted near the back wall of a shallow cabinet.
Breaking capacity by voltage — the 187 kA figure governs the main, but the 690 V rating is the limiting case
The 187 kA at 240 V is the headline number, but the 17 kA at 690 V is the binding constraint for 690 V systems. If your panel feeds a 690 V motor drive, this breaker's SCCR at that voltage is 17 kA — coordinate with the upstream transformer or main breaker to ensure the fault current doesn't exceed that. For 400/415 V systems, 121 kA is still generous headroom for most industrial service entrances.
Temperature derating — the 400 A rating holds through 50 °C
The breaker carries its full 400 A rating from 40 °C through 50 °C ambient. Above that, derate linearly: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If the breaker is mounted in a high-ambient enclosure near other heat sources, use the 55 °C or 60 °C column for the continuous current limit rather than the 40 °C rating.
Auxiliary and trip accessories — built-in, no external module needed
The breaker ships with 2 auxiliary switches, 1 trip alarm switch, and 1 electrical alarm switch — all integrated. The shunt trip release (STL) is factory-installed. The supplied basic switch is order code 3VA2340-5HN32-0AA0, and the integrated auxiliary trip is 3VA9688-0BL33. No undervoltage release, phase failure detection, or communication function is included; this is a straightforward line-protection breaker without network connectivity.