What it is and what it does
The Siemens SENTRON 3VA2325-5HL42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 250 A continuous current, designed for line protection in distribution panels. It carries an ETU320 electronic trip unit, which provides adjustable overload and short-circuit protection curves. The breaker's insulation voltage is rated at 800 V, and the front face carries IP40 protection — suitable for enclosed panel mounting where the front is accessible but the live parts remain behind the door.
Breaking capacity — what the numbers mean for coordination
The interrupting ratings span the common system voltages: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V. The 187 kA at 240 V is the headline figure — it tells you this breaker can clear a bolted fault on a low-voltage secondary without upstream fuses needing to open first. At 690 V the capacity drops to 7.5 kA, which is still adequate for most 690 V motor circuits but means you need to verify the available fault current at that voltage level. The ETU320 release lets you set the long-time pickup and short-time delay, so you can coordinate selectively with downstream breakers.
Thermal performance and derating
The breaker holds its full 250 A rating from 40 °C through 70 °C ambient — no derating needed across that range. That simplifies panel layout: you don't have to oversize the frame or add forced cooling just because the breaker sits near other heat sources. The maximum power loss at rated current is 37.5 W per pole, which is typical for a 250 A frame and manageable in a ventilated enclosure.