What it is and what it does
The Siemens 3VA1112-4FF46-0AA0 is a SENTRON molded case circuit breaker (MCCB) with four poles, rated for a continuous current Iu of 125 A and carrying a TM240 thermal-magnetic trip unit. That 125 A holds through 50 °C ambient; at 70 °C it derates to 114 A, so if your panel runs hot you size for the derated number, not the label. Interrupting capacity hits 121 kA at 240 V and 75.6 kA at 415 V — that's serious fault-current headroom for a main or feeder breaker in a 480 V industrial panel. At 690 V it still clears 11.9 kA.
Where it lands in the panel
This MCCB fits a standard DIN-rail or panel-mount footprint — 101.6 mm wide, 130 mm tall, 70 mm deep. The IP40 front protection means it's fine inside a closed enclosure but not for washdown areas. Four poles let it switch three-phase plus neutral, with the N-conductor protection set at 50% of the phase rating.
Trip unit and adjustability
The TM240 thermal-magnetic release has an adjustable magnetic trip (li) up to 1250 A, so you can dial the instantaneous pickup to coordinate downstream. No ground-fault monitoring on this version, and no onboard communication — it's a straight line-protection breaker. Maximum power loss is 28.1 W, worth factoring into your enclosure thermal budget.