What this MCCB is and what it does
The Siemens 3VA2340-5JQ32-0CL0 is a SENTRON 3VA2 molded case circuit breaker (MCCB) designed for line protection in distribution panels. It's a 3-pole unit with an adjustable thermal-magnetic trip unit covering 600 A to 4000 A, and a continuous current rating of 400 A at 40 °C. The interrupting capacity hits 187 kA at 240 V AC, dropping to 121 kA at 415/440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V — so it handles high-fault utility feeds and transformer secondaries without cascading upstream.
Thermal derating and what it means for your panel
This breaker holds 400 A continuously from 40 °C up to 50 °C, then derates linearly: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. If your panel ambient runs above 50 °C — say a tightly packed switchgear lineup — you need to account for that drop. The 110 mm depth, 138 mm width, and 248 mm height fit standard MCCB mounting footprints; the 98.5 W max power loss means ventilation slots or forced air above 60 °C ambient are worth planning for.
Auxiliaries and releases built in
Factory-fitted with an undervoltage release (UVR) and a full complement of auxiliary switches: 2 auxiliary switches + 1 trip alarm switch + 1 electrical alarm switch (HQ type). That covers remote status, trip indication, and undervoltage protection without adding external relays. The basic switch variant is 3VA2340-5JQ32-0AA0 — this -0CL0 suffix adds the UVR and communication function.