Rating and fit for the panel
The Siemens SENTRON 3VA1125-5EF32-0AA0 is a 3-pole molded case circuit breaker rated 25 A at 40 °C, with a TM240 thermal-magnetic release — the thermal element carries the continuous load, the magnetic trip handles short-circuit protection. Front IP40 protection means it's splash-safe in a closed enclosure but not washdown-rated; mount inside a cabinet for environments with dust or moisture.
Current derating across temperature
Rated current holds at 25 A up to 50 °C ambient, then drops to 24 A at 55–60 °C and 23 A at 65–70 °C. That derating curve matters if the breaker sits near transformers or drives that push panel internal temperature above 50 °C — you lose about 8 % of the continuous rating at the high end.
Short-circuit breaking capacity varies with system voltage: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 500/690 V. At 400 V class (common in European panels) the 121 kA rating is well above typical transformer fault levels — no need to cascade an upstream current-limiting fuse in most installations.
Physical footprint and mounting
Dimensions: 130 mm height, 76.2 mm width (3 in), 70 mm depth. Power loss is 8.5 W maximum, which is low enough to avoid forced ventilation in a typical 600 mm wide enclosure.