What this MCCB carries — and what it means on a real panel
The Siemens 3VA2440-7HL42-0AA0 is a 4-pole SENTRON molded case circuit breaker rated for 400 A continuous current across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling. That flat thermal curve is the headline: it means the breaker holds its full 400 A rating in a warm enclosure without a sizing penalty, which simplifies panel build for high-density switchboards. 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 drop to 9 kA at 690 V. That 330 kA figure at 240 V tells you this breaker is built for high-fault utility entrance or large transformer secondary duty where available fault current is extreme. The ETU320 electronic trip unit gives adjustable long-time, short-time, instantaneous, and ground-fault protection — it's a programmable curve, not a fixed thermal-magnetic.
Physical fit and panel integration
Dimensions are 248 mm high, 184 mm wide, 110 mm deep. That 184 mm width across 4 poles is standard for a 400 A frame — it occupies the same footprint as other SENTRON 3VA 4-pole breakers in this current class. The 110 mm depth leaves clearance for rear-connected busbars or cable lugs in a typical switchboard section.
Selectivity and coordination notes
With a minimum trip setting of 600 A and maximum of 4 800 A (via the ETU320), this breaker can be selectively coordinated downstream of a larger main or upstream of distribution MCCBs. The 63.5 W maximum power loss at rated current matters for enclosure thermal rise calculations — factor it into the switchgear ventilation design.