What this MCCB does for a line
The Siemens 3VA2125-8KQ36-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for 25 A continuous current on a 3-pole line-protection circuit. Its adjustable thermal-magnetic trip unit covers a range from 38 A minimum to 300 A maximum, so it can be field-set to protect a specific load without swapping the breaker body. Breaking capacity is the headline here: 440 kA at 240 V AC, 330 kA at 415 V and 440 V, 220 kA at 500 V, and 52.5 kA at 690 V. Those numbers mean this breaker can safely interrupt very high fault currents on a distribution transformer secondary or a large motor-circuit fault without welding its contacts or rupturing the case. It includes a communication function and a ground-fault monitoring version using summation current formation on the L-conductor, so it can report status or trip events to a PLC or BMS over a fieldbus — useful for condition monitoring in a process line where you need to know which breaker opened and why.
Panel fit and mounting
Dimensions are 105 mm wide, 181 mm high, 86 mm deep. That width matches the standard 3-pole MCCB footprint for a SENTRON panelboard or a separate enclosure. The depth leaves room behind the door for wiring and a neutral bar. Rated insulation voltage is 800 V, so it can be used on 480/277 V or 600 V distribution systems without derating the insulation clearance. Operating temperature range is -25 °C to +70 °C, with storage from -40 °C to +80 °C. That covers most indoor industrial environments; if the panel sits in an unheated warehouse, the storage limit handles it.