What this MCCB delivers for the line
The Siemens SENTRON 3VA2340-5JQ42-0KA0 is a 4-pole molded case circuit breaker rated for 400 A continuous current at 40 °C, with an electronic trip unit ETU560. It handles fault currents up to 187 kA at 240 V and 121 kA at 415 V, so it clears high-energy faults without cascading upstream — critical for main or feeder protection in a distribution panel.
Breaking capacity and selectivity headroom
At 415 V the breaker is rated 121 kA, at 500 V it still holds 75.6 kA, and at 690 V it drops to 17 kA. That 121 kA at 415 V gives solid selectivity with downstream 25 kA or 36 kA rated breakers — you can coordinate without oversizing the whole string. The 187 kA at 240 V covers high-fault industrial services where transformer impedance is low.
Thermal derating and panel integration
The breaker holds 400 A up to 50 °C ambient, then 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 panel with multiple devices, expect to apply the 55 °C or 60 °C figure. The 184 mm width and 248 mm height fit standard SENTRON 3VA mounting footprints — no special adapter needed for a 4-pole 400 A frame.
Trip unit and auxiliary functions
The ETU560 electronic trip unit supports adjustable LSI protection (long-time, short-time, instantaneous) plus ground-fault monitoring via summation current formation on L+N conductors. A shunt trip (STL) is integrated for remote tripping. Communication function is present — the ETU560 can interface with the SENTRON powerconfig software for settings and event logging. There is no undervoltage release, no auxiliary contact, and no phase-failure detection on this variant.