The Siemens 3VA2340-6JP32-0AJ0 is a SENTRON molded case circuit breaker (MCCB) rated for 400 A continuous current, with an ETU550 electronic trip unit and a 3-pole configuration. Its 242 kA interrupting rating at 240 V AC means it can safely clear very high fault currents on the secondary side of a large distribution transformer without upstream coordination issues — a critical spec for high-fault-capacity panels in industrial switchgear.
Breaking capacity across voltages
The interrupting rating drops as system voltage rises: 187 kA at 415 V and 440 V, 121 kA at 500 V, and 40 kA at 690 V. That 40 kA at 690 V still covers most industrial 690 V distribution panels, but verify your available fault current at the point of installation — if your SCCR calculation lands above 40 kA at 690 V, this breaker won't hold.
Thermal derating and panel integration
Full 400 A rating holds through 50 °C ambient; above that it derates to 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. In a sealed enclosure with other heat sources, that 55 °C derate is the one to watch — a 400 A bus rated for a 40 °C panel loses 25 A if the internal ambient climbs. The 110 mm depth and 138 mm width fit standard MCCB mounting footprints, but the 248 mm height needs clearance for the rotary handle and arc-chamber venting.
Trip unit and auxiliary contacts
The ETU550 electronic trip unit provides adjustable long-time, short-time, instantaneous, and ground-fault protection curves — it's the mid-range electronic trip in the 3VA line, suitable for feeder and main breaker duty where coordination selectivity matters. The auxiliary contact block includes 2 auxiliary switches plus 1 trip alarm switch (HP type), giving remote status feedback without a separate module. Maximum power loss is 96 W, which factors into enclosure thermal calculations.