What this MCCB delivers
The Siemens SENTRON 3VA2440-7HL32-0AJ0 is a 3-pole molded case circuit breaker rated for 400 A continuous current across its full ambient range of 40 °C to 70 °C — no derating needed up to the top of that band. That flat thermal curve is the headline feature for panel builders: it simplifies coordination in a warm enclosure where other breakers would force a frame size bump. The adjustable instantaneous trip range spans 600 A to 4800 A, letting you dial in selectivity with downstream devices without swapping the breaker. At 240 V the interrupting rating hits 330 kA; at 415 V and 440 V it holds at 242 kA, dropping to 187 kA at 500 V and 9 kA at 690 V. That 330 kA figure at 240 V is high for a 400 A frame — it covers high-fault locations like transformer secondaries or large motor control centers without needing a current-limiting fuse ahead of it. Maximum power loss is 63.5 W — relevant for thermal management inside a sealed panel. The breaker ships as a line-protection device (no ground-fault monitoring, no undervoltage release, no communication module) with a basic switch configuration of 2 auxiliary switches plus 1 trip alarm switch (HP type). The base order code is 3VA2440-7HL32-0AA0; this -0AJ0 variant adds the specified auxiliary contact package.
Panel fit and integration
Dimensions are 248 mm high × 138 mm wide × 110 mm deep — a standard 3-pole MCCB footprint for this current class. The depth of 110 mm (4.33 in) is compact enough for shallow backpanel layouts; verify gland-plate clearance against the 248 mm height when mounting in a row with other breakers. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The 70 °C operating ceiling matches the top of the flat derating curve, so the breaker delivers its full 400 A even in a hot enclosure near the top of a panel.