What this MCCB is and what it does
The Siemens 3VA1112-3ED22-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. Its 2-pole construction with a TM210 thermal-magnetic release handles overload and short-circuit protection in a single unit, rated for a 125 A continuous load at 40 °C ambient. The TM210 release means the thermal element is fixed at 125 A — no interchangeable rating plugs — so the breaker is sized for a specific load and cannot be field-adjusted upward. The magnetic trip threshold is factory-set to coordinate with the thermal curve, giving a defined instantaneous pickup for short-circuit events.
Key ratings and what they mean for your panel
Interrupting capacity is 75.6 kA at 240 V AC and 52.5 kA at 415 V AC — figures that cover most industrial service-entrance and feeder applications. At 415 V, the 52.5 kA rating means this breaker can safely clear a fault up to that level without upstream fuses or a current-limiting reactor, provided the available fault current at the panel does not exceed that value. The thermal derating curve is published: 125 A from 40 °C through 50 °C, then 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. If the breaker lives in a hot enclosure — say next to a transformer or in a non-ventilated cabinet — the 70 °C derated figure of 114 A is the actual continuous rating you must design to. Maximum power loss is 18.74 W. In a dense panel with multiple breakers side by side, that heat adds to the internal ambient and accelerates the derating effect — something to check if you are packing several 125 A frames into a small enclosure.
Physical fit and panel integration
The 3VA1112-3ED22-0AA0 measures 70 mm deep, 50.8 mm wide (2 inches), and 130 mm high. The 2-inch width per pole is standard for SENTRON 3VA frames, so it occupies one 2-pole module on the DIN rail or panel-mount footprint. Depth of 70 mm means it clears most 120 mm-deep enclosures with room for wiring gutters. Front face carries an IP40 protection class — splash protection is not provided, so the breaker belongs in a closed cabinet, not in a washdown zone. No trip indicator, no undervoltage release, no communication function on this variant — it is a straight thermal-magnetic breaker with no auxiliary electronics.