The Siemens SENTRON 3VA1225-4EF42-0AH0 is a 4-pole molded case circuit breaker (MCCB) designed for line protection. It carries a TM240 thermal-magnetic release and is rated for 250 A continuously at 40 °C ambient, with a rated insulation voltage of 800 V. The interrupting ratings hit 121 kA at 240 V AC and 75.6 kA at 415 V AC, giving real headroom for high-fault installations like industrial mains or transformer feeders.
SCCR and selectivity
With 121 kA at 240 V and 75.6 kA at 415 V, this MCCB handles high available fault current without upstream fusing. The 4-pole construction suits three-phase plus neutral or switched-neutral applications. The TM240 release provides thermal-magnetic overload and short-circuit protection, adjustable via the rating plug. Rated insulation voltage of 800 V means the breaker can be used in 690 V systems, where it still interrupts 11.9 kA. The 57 W maximum power loss is manageable for enclosed panel layouts but should be considered in sealed, high-density cabinets.
Dimensions and mounting
The breaker measures 70 mm deep, 140 mm wide, and 158 mm high. It mounts on a DIN rail or directly to a backplate via the base. The 4-pole width of 140 mm is standard for this frame size, so it fits existing SENTRON panel cutouts and busbar systems.
Auxiliary and alarm contacts
Factory-fitted with 2 auxiliary switches plus a separate trip alarm switch (HQ type). The auxiliary contacts signal the breaker's open/closed position; the trip alarm switch indicates a fault trip. No undervoltage release or ground-fault module is included — those are add-on accessories if needed.