The Siemens SENTRON 3VA1125-5EF32-0AE0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a 25 A continuous current at 40 °C and a TM240 thermal-magnetic overcurrent release. Its interrupting capacity hits 187 kA at 240 V, 121 kA at 415 V, and 75.6 kA at 440 V — numbers that tell you it handles high-fault utility feeds and large transformer secondaries without cascading upstream. The 800 V rated insulation voltage (Ui) covers 480 V and 600 V class panels with headroom. IP40 on the front means it's fine in a dry indoor enclosure; no washdown rating here.
Breaking capacity and current derating
The 187 kA at 240 V is the headline number, but the real-world fit depends on the system voltage. At 415 V it still clears 121 kA; at 440 V it drops to 75.6 kA; at 690 V it's 17 kA. If your panel's available fault current at the breaker line side exceeds those figures at the operating voltage, you need a current-limiting upstream device or a higher-rated frame. The 25 A rating holds flat from 40 °C through 50 °C, then derates to 24 A at 55 °C, 23.5 A at 60 °C, 23 A at 65 °C, and 22.5 A at 70 °C — so in a hot enclosure or near other heat sources, plan the load at the derated value, not the nameplate.
Mounting and panel fit
The 3VA frame measures 76.2 mm wide, 130 mm tall, and 70 mm deep. That width is a standard 3-pole MCCB footprint for this class — it fits the same DIN-rail or screw-mount pattern as other 3VA 3-pole units. The 4 auxiliary switches (HQ type) ride on the side, adding about one module width. Plan the enclosure depth to clear the 70 mm body plus wiring space behind the line/load lugs.
Release and accessory configuration
The TM240 release is a fixed thermal-magnetic type — no electronic adjustment, no communication module, no phase-failure detection, no undervoltage release, no ground-fault monitoring. The auxiliary contact version ships with 4 HQ (high-utilization) switches. If your application needs a shunt trip, UVR, or communication, this variant does not carry them; you'd step to a different suffix in the 3VA family. The trip indicator is absent, so there's no local mechanical flag showing the breaker tripped on fault.