What this MCCB is and what it does
The Siemens SENTRON 3VA2440-6HN32-0AF0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection in distribution panels. It carries 400 A continuously across the full 40 °C to 70 °C ambient range — no derating needed up to that ceiling — on a 4800 A frame. The interrupting ratings are the headline: 242 kA at 240 V AC, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 9 kA at 690 V. That 242 kA at 240 V is what you spec when the utility transformer is right next to the main switchboard and the available fault current is high. The 187 kA at 415 V covers most European industrial supply points. At 690 V the 9 kA rating is lower — this is a line-protection breaker, not a motor-starting device, so the 690 V figure matters only if you are feeding a 690 V bus with high fault capacity.
Sizing and selectivity — what the ratings mean for the panel
The 4800 A frame is the mechanical platform; the 400 A continuous rating is the thermal-magnetic or electronic trip unit setting. That means this breaker can be ordered with lower amp ratings in the same frame, but the 3VA2440-6HN32-0AF0 ships set for 400 A. The 1-second limited rating of 5 kA is the short-time withstand — important for selective coordination downstream. If you are coordinating with a 100 A feeder breaker, this 400 A main will hold in for a fault on the branch long enough for the downstream device to clear, provided the fault current stays under 5 kA for the first cycle. The trip indicator gives a local mechanical flag so the panel walker sees which pole tripped without opening the door.
Physical fit and integration
Dimensions are 248 mm high, 138 mm wide, 110 mm deep. That depth is the body only — add projection for the rotary handle or extended terminals. The 138 mm width is standard for a 3-pole SENTRON 3VA2 frame; it fits the same mounting footprint as other 3VA2 3-pole breakers. The breaker is designed for screw-mounting to a backplate or mounting plate in a distribution panel — not DIN-rail snap-on. The 63.5 W maximum power loss at rated current means the panel designer needs to account for that heat in the enclosure sizing; a sealed stainless enclosure will need forced ventilation or a larger volume to stay below the 70 °C operating maximum.