The Siemens 3VA2340-6JP32-0KC0 is a SENTRON molded case circuit breaker (MCCB) rated for 400 A continuous at 40 °C, with a 242 kA interrupting capacity at 240 V AC. It's a line-protection variant with an ETU550 electronic trip unit and built-in communication capability — meaning you can pull current and status data upstream without adding a separate metering module. This is a current-production part, so no last-time-buy scramble.
The 400 A rating holds at 40 °C ambient, but above that you lose headroom: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. If your enclosure runs warm — say a packed MCC lineup — size the breaker for the actual ambient, not the nameplate. The ETU550 trip unit gives you LSIG (long-time, short-time, instantaneous, ground-fault) adjustability, so coordination studies are practical. Breaking capacity scales with system voltage: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 40 kA at 690 V. At 415 V — common in industrial distribution — 187 kA is well above typical fault levels, giving selectivity headroom without cascading upstream.
Integration and auxiliary options
Three-pole, 138 mm wide, 248 mm tall, 110 mm deep. The depth is the dimension that catches people on retrofit — check that the existing enclosure has clearance for the rear arc-chamber exhaust. The basic switch (the breaker body without electronics) is order code 3VA2340-6JP32-0AA0, and the integrated auxiliary trip module is 3VA9688-0BL33 — useful if you're ordering spares or building a replacement from sub-assemblies.