What this 400 A MCCB carries — and where it fits
The Siemens 3VA2440-5HM32-0AA0 is a SENTRON molded case circuit breaker, 3-pole, rated 400 A continuous at ambient temperatures from 40 °C through 70 °C with no derating — that's a full 400 A all the way up to 70 °C, so you don't lose capacity on a hot panel floor or inside a crowded enclosure. The ETU330 electronic trip unit handles the overcurrent protection curve, and the breaker is rated for line protection duty (cable and busbar feeder protection, not motor starting). Breaking capacity is the headline: 187 kA at 240 V AC, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 9 kA at 690 V. That 187 kA at 240 V is a high-interrupting rating — it's sized for large transformer secondaries or high-fault industrial services where a standard 65 kA or 100 kA MCCB would need upstream fuses or a current-limiting reactor. The 5 kA limited-to-1-second rating is the short-time withstand for selective coordination with downstream breakers.
Lifecycle and sourcing posture
Rated insulation voltage is 800 V, and the operating voltage is 690 V AC — so it's suitable for 480 V and 600 V class systems with headroom. Front IP40 protection means it's fine for a standard enclosed panel; not rated for washdown or outdoor exposure without an additional enclosure.
Panel fit and physical integration
Dimensions are 248 mm high, 138 mm wide, 110 mm deep — a standard 3-pole MCCB footprint for the SENTRON 3VA platform. It mounts on a DIN rail or can be screw-fixed to a backplate. No undervoltage release, no shunt trip, no communication module on this variant; it's a straight line-protection breaker with the ETU330. If you need auxiliary contacts or remote indication, those are add-on accessories that clip onto the side or front.