MCCB for 400 A line protection
The Siemens SENTRON 3VA2440-5HN32-0BC0 is a 3-pole molded case circuit breaker (MCCB) rated for line-protection duty. It carries a continuous 400 A from 40 °C through 70 °C with no derating across that range, so the full ampacity holds in a warm enclosure. Breaking capacity hits 187 kA at 240 V AC, 121 kA at 415 V and 440 V AC, then drops to 75.6 kA at 500 V and 9 kA at 690 V. For a 400 A frame, the 121 kA at 415/440 V covers most industrial service-entrance and distribution panel requirements without an upstream current-limiting fuse. Built-in undervoltage release (UVR) and two HQ auxiliary switches come factory-fitted. The UVR trips the breaker on loss of control voltage — standard for safety disconnects where a voltage dip must open the load circuit.
Panel fit and integration
Dimensions are 248 mm high, 138 mm wide, 110 mm deep. The 3-pole frame occupies a standard MCCB footprint on a DIN rail or bolted busbar mount. Verify gland-plate cutout against the 138 mm width before panel layout. Maximum power loss is 66 W at rated load. Factor that into enclosure thermal calculations — at 400 A continuous, the heat dissipation is non-trivial and may drive ventilation or a larger cabinet. Operating temperature range is -25 °C to 70 °C; storage from -40 °C to 80 °C. The 70 °C operating ceiling matches the top of the flat derating curve, so the breaker stays at 400 A right up to that limit.
Lifecycle and sourcing
The basic switch core is order code 3VA2440-5HN32-0AA0 — that is the bare switching module without auxiliary releases. The -0BC0 suffix adds the factory-fitted undervoltage release and two HQ aux switches, so it arrives ready for a panel that requires UVR on the line feeder. No communication function is built in (no Modbus, PROFIBUS, or Ethernet interface on this variant). If you need breaker-level energy monitoring or remote trip indication, look at the 3VA2 with communication module option.