What this MCCB carries and where it fits
The Siemens SENTRON 3VA2440-7MN32-0KF0 is a 3-pole molded case circuit breaker rated for 400 A continuous current across the full ambient range from 40 °C up to 70 °C — no derating needed up to that ceiling. It's the motor-protection version with an ETU350M overcurrent release and built-in phase failure detection, so it's sized for a 400 A feeder or large motor branch circuit in a 480 V / 600 V class panel. The interrupting ratings climb to 330 kA at 240 V and hold at 242 kA through 440 V, then step to 187 kA at 500 V and 9 kA at 690 V. That 330 kA figure at 240 V means it can be applied on the secondary side of a large transformer or in a high-fault industrial service entrance without needing a current-limiting upstream device — the breaker clears the fault itself.
Physical fit and panel integration
The case measures 138 mm wide, 248 mm high, and 110 mm deep — a standard SENTRON 3VA footprint that drops into the same mounting cutout as other 400 A frames in the series. Front IP40 protection covers the operator interface; the body is designed for DIN-rail or screw-mount panel installation with lug-type line and load connections.
Release and protection parameters
The ETU350M electronic trip unit offers adjustable short-time delay (tsd) from 0 s to a maximum setting, and adjustable response time (tr) with a minimum of 4 and maximum of 17 — these let the engineer coordinate with downstream breakers and upstream switchgear on a selective coordination study. The breaker draws a maximum power loss of 63.3 W at rated load, which matters for enclosure thermal rise calculations. Latching endurance is rated at 15,000 operations.