What this MCCB delivers — and what it doesn't
The Siemens SENTRON 3VA1125-5EE32-0BF0 is a 3-pole molded case circuit breaker rated 25 A continuous at 40 °C, with an interrupting capacity of 187 kA at 240 V AC. That 187 kA rating means it can safely clear a fault up to that level without the arc flashing over or the breaker rupturing — critical for high-fault-current panels near large transformers or utility feeds. The interrupting curve drops to 121 kA at 415 V and 75.6 kA at 440 V, so verify the available fault current at your service voltage before committing the BOM line. This is a line-protection design — not a motor-protective breaker with integrated overloads. It sits upstream of a motor starter or downstream of a main breaker, clearing short-circuits while leaving overload coordination to a separate thermal-magnetic or electronic relay. The built-in undervoltage release (UVR) drops the breaker open when control voltage falls below a set threshold, which is useful for safety circuits that need to guarantee a de-energized state on power loss.
Panel fit and mounting
The breaker measures 76.2 mm wide, 130 mm tall, and 70 mm deep — a standard SENTRON 3VA1 footprint that fits existing DIN-rail or screw-mount panel layouts. The 70 mm depth is shallow enough to clear most gland plates and back-panel wiring ducts without forcing a deeper enclosure. The auxiliary switch and trip alarm switch (1 each, HQ design) snap into the accessory slot on the left side; wire them before the breaker is bolted in for easier access. Ambient temperature derating is minimal up to 50 °C — still 25 A — then drops to 24 A at 55 °C and 23 A at 70 °C. If the panel runs hot (say, crowded with drives or transformers), size the load at the 70 °C figure, not the 40 °C nameplate. The rated insulation voltage of 800 V covers 480 V and 600 V class systems with margin.
What's on the nameplate
The breaker ships with a trip indicator (mechanical flag on the handle) so a technician can see at a glance whether it tripped on fault versus being manually switched off. There is no voltage trigger, no communication function, and no ground-fault monitoring version on this variant — it is a straightforward line-protection MCCB with undervoltage release and one auxiliary plus one alarm switch. The supplied basic switch is order code 3VA11255EE320AA0. Storage temperature range is -40 °C to 80 °C; operating range is -25 °C to 70 °C. Maximum power loss is 11 W, which matters for enclosure heat load calculations when multiple breakers are ganged.