MCCB for motor protection — 250 A, 3-pole, ETU350M release
The Siemens SENTRON 3VA2325-5MN32-0AC0 is a 3-pole molded case circuit breaker (MCCB) rated for a continuous current Iu of 250 A, built specifically for motor protection duty. It carries an ETU350M electronic overcurrent release with phase failure detection, so it can handle the inrush and thermal characteristics of a motor load without nuisance tripping on start-up — that's the difference between a general-purpose MCCB and one specced for motor branch circuits. Breaking capacity is 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 17 kA at 690 V. That 187 kA at 240 V tells you this breaker is sized for high-fault installations — think large transformer secondaries or busway taps where the available fault current is well above what a standard 65 kA or 100 kA MCCB can interrupt. The 17 kA at 690 V still covers most 690 V industrial distribution. Thermal derating is published across the operating range: 250 A flat from 40 °C through 50 °C, then 240 A at 55 °C, 235 A at 60 °C, 230 A at 65 °C, and 225 A at 70 °C. If your panel ambient sits at 55 °C, plan for 240 A continuous — the breaker won't hold 250 A without nuisance tripping at that temperature.
Panel fit and integration
Footprint is 138 mm wide by 248 mm tall by 110 mm deep. That 138 mm width is a standard 3-pole MCCB form factor for this current class — it fits the same panel cutout and bus-bar spacing as other SENTRON 3VA2 250 A frames. The IP40 front protection means the breaker face is protected against tools and small wires, but the enclosure itself needs to handle the rest of the IP rating. Maximum power loss is 37.5 W. In a sealed, low-ventilation panel, that heat needs to be factored into the thermal budget — especially if the breaker is mounted alongside other high-current devices. The 15 000 latching endurance cycles give a reasonable mechanical life for a motor-protection breaker in a production line that cycles a few times a shift.
Lifecycle and sourcing
It ships with 2 auxiliary switches (HQ type) pre-installed. There is no undervoltage release, no ground-fault monitoring module, and no communication function on this variant — those are separate order-code options if the application needs them. The supplied basic switch is 3VA2325-5MN32-0AA0, which is the core switching mechanism inside the molded case.