What this MCCB carries — and where the numbers matter
The Siemens SENTRON 3VA2340-5JQ42-0HL0 is a 4-pole molded case circuit breaker rated 400 A continuous at 40 °C, with a full-scale setting of 400 A and an initial trip threshold of 80 A. Its interrupting capacity hits 187 kA at 240 VAC, dropping to 121 kA at 415/440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V — so the voltage class of your distribution bus determines whether this breaker clears a fault or the fault clears upstream. Designed for line protection (cable/feeder), not motor branch, with a communication function for remote monitoring or trip indication.
Thermal derating — the real-world current limit
At 40, 45, and 50 °C ambient the breaker holds its 400 A rating. Above that it derates: 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. If your panel runs hot — say a non-ventilated enclosure near a furnace line or a packed MCC section — the 70 °C figure is the one to design to, not the catalog 400 A.
Dimensions and panel fit
The 3VA2340-5JQ42-0HL0 measures 248 mm high, 184 mm wide, 110 mm deep — a 4-pole frame that fits standard SENTRON mounting plates. The 110 mm depth (4.33 in) leaves clearance behind a 200 mm deep enclosure door without interfering with gland plates or busbar shrouds. Auxiliary switch configuration is 2 auxiliary switches + 1 trip alarm switch + 1 electrical alarm switch HQ, plus a shunt trip (STL) release for remote tripping.
Operating range and power loss
Operating temperature spans -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss at rated current is 96 W — enough to factor into enclosure thermal calculations if the MCCB is in a sealed cabinet with other heat sources.