The Siemens SENTRON 3VA2125-5MP36-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated at 25 A continuous and designed specifically for motor protection, using the ETU550M electronic trip unit. It's a current-production part — no end-of-life notice on this order code. Breaking capacity is the headline here: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 3.7 kA at 690 V. That 187 kA at 240 V means it can safely clear a fault on a high-capacity transformer secondary without the arc flashing over — critical for panel protection in large distribution boards. The thermal derating is flat across the full temperature range: 25 A from 40 °C all the way up to 70 °C. No need to downrate for a hot enclosure — that simplifies panel design in non-climate-controlled environments.
Motor protection and trip unit
The ETU550M trip unit is the electronic brain here — it provides adjustable overload protection, short-circuit protection, and ground-fault monitoring (though this variant ships without ground-fault detection). Phase failure detection is built in, which is essential for three-phase motor protection: if a phase drops, the breaker trips before single-phasing cooks the winding. Communication function is included, meaning this breaker can report status and trip events to a PLC or BMS over the SENTRON communication bus — useful for remote monitoring on a motor control center. Operating power at AC-3 duty (motor switching) is 5.5 kW at 230 V — that's the real-world motor rating for a standard three-phase induction motor. The 25 A frame covers most small-to-medium pump, fan, and conveyor motors.
Panel fit and mounting
Footprint: 105 mm wide, 181 mm tall, 86 mm deep. That's a standard SENTRON 3VA2 frame size — it clips onto the DIN rail or mounts via the screw terminals. The 86 mm depth means it fits in shallow enclosures where full-height MCCBs won't clear the door. IP40 on the front — protected against tools and small wires touching live parts, but not sealed against water. Mount inside a panel rated for the environment.