400 A MCCB with ETU350 — what the ratings mean for your panel
The Siemens SENTRON 3VA2440-5HN32-0AA0 is a 3-pole molded case circuit breaker rated for 400 A continuous current at 40 °C through 70 °C, meaning it holds full ampacity across a wide ambient range without derating — a real advantage in a crowded enclosure where heat builds. The ETU350 electronic trip unit gives you adjustable long-time, short-time, and instantaneous protection curves, so you coordinate selectively with downstream breakers rather than relying on a fixed thermal-magnetic characteristic. Interrupting capacity runs 187 kA at 240 V, 121 kA at 415/440 V, 75.6 kA at 500 V, and 9 kA at 690 V — that covers most industrial service-entrance and feeder applications where fault current is high.
Panel fit and thermal budget
At 248 mm high, 138 mm wide, and 110 mm deep, this breaker fits standard SENTRON 3VA switchboard and panelboard footprints. The maximum power loss of 63.5 W factors into your enclosure's thermal calculation — it's not negligible in a sealed cabinet, so account for it in the ventilation or cooling plan.