The Siemens SENTRON 3VM1125-3ED12-0AA0 is a 1-pole molded case circuit breaker (MCCB) with a TM210 thermal-magnetic release. Rated at 25 A continuous (Iu) across the 40 °C to 50 °C band, it derates to 23 A at 70 °C. The interrupting capacity hits 53 kA at 240 V AC and 7.5 kA at 415 V AC — that 53 kA figure means it can clear a high-fault bolted short on a 240 V line without the arc flashing upstream to the main breaker. That's the spec that decides whether this breaker holds coordination in a panel with a 65 kA-rated main.
Integration and mounting
The 3VM1125-3ED12-0AA0 snaps onto a standard DIN rail. At 25.4 mm wide (1 inch) and 70 mm deep, it takes one pole position in a panel — that's another SKU that fits the same bin footprint as other 1-pole SENTRON MCCBs. IP40 on the front means it's fine inside a closed panel; no washdown rating, so keep it out of wet environments. The TM210 release is fixed thermal (25 A) with a magnetic short-circuit pickup adjustable from 320 A (li min) to 320 A (li max) — essentially a fixed magnetic threshold at 320 A, so don't expect to dial the instantaneous trip down for a sensitive load.
What the ratings mean for fit
The 53 kA at 240 V is the headline number — it's the SCCR (short-circuit current rating) at that voltage. If your panel's available fault current is 50 kA at 240 V, this breaker holds. At 415 V the interrupting capacity drops to 7.5 kA, which is typical for a 1-pole MCCB at line-to-line voltage; verify your point-of-fault current doesn't exceed that. The 25 A continuous rating holds steady up to 50 °C, then derates linearly to 23 A at 70 °C — so in a hot panel near the top of a cabinet, you lose 2 A of headroom. The TM210 release means thermal overload protection is fixed at 25 A; no field adjustment on the thermal element. The magnetic trip is set at 320 A (li), which is about 12.8x In — that's a high instantaneous pickup, typical for motor-starting or transformer inrush where you don't want nuisance trips on the magnetizing current.