What it is and what the ratings mean
The Siemens 3VA1112-4EF32-0DH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. Its headline rating is 125 A at 40 °C, meaning it carries that current continuously in a 40 °C ambient without derating; at 70 °C it still holds 114 A, which is the figure to check if the breaker lives in a hot enclosure next to other dissipating gear. Breaking capacity is 121 kA at 240 V — that is the maximum fault current it can safely interrupt at that voltage. At 415 V it still handles 75.6 kA, and at 690 V it drops to 11.9 kA. For a 480 V panel the relevant figure is the 415 V rating (the closest standard voltage below 480 V in the evidence), which covers most North American industrial service-entrance requirements. Three poles, 800 V rated insulation voltage. The breaker ships with an undervoltage release (UVR) and a complement of 2 auxiliary switches plus 1 trip alarm switch — enough for remote status indication and a shunt-trip-style drop on loss of control voltage.
Deployment context
This MCCB mounts on a DIN rail or directly to a backplate in a standard 3-pole footprint: 76.2 mm wide (3 inches), 130 mm tall, 70 mm deep. The width matches a standard 3-pole MCCB cutout, so it drops into existing panel layouts without re-drilling. Rated for operation from -25 °C to 70 °C, storage from -40 °C to 80 °C.