125 A MCCB with 220 kA interrupting capacity — what the ratings mean for your panel
The Siemens 3VA1112-6EF32-0JH0 is a 3-pole SENTRON molded case circuit breaker (MCCB) rated 125 A continuous at 40 °C through 50 °C, with a slight thermal derating curve: 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. That means in a warm enclosure — say a panel running at 55 °C ambient — you still get 122 A of continuous capacity, not a hard drop. The interrupting ratings climb steeply with voltage: 220 kA at 240 V, 154 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V. For a 480 V distribution panel in North America, the 75.6 kA SCCR at 440 V is the relevant figure — that's well above typical fault currents for most industrial services. The breaker is designed for line protection (not motor or feeder protection variants), and it carries a shunt trip (STL) auxiliary release plus a complement of 2 auxiliary switches and 1 trip alarm switch HQ.
Mounting and integration — panel fit
The breaker measures 70 mm deep, 76.2 mm wide, and 130 mm high — a standard 3-pole MCCB footprint that drops into a SENTRON 3VA panelboard or a DIN-rail adapter. The 76.2 mm width (3 inches) is the critical dimension for multi-pole ganging and busbar alignment. Power loss is 28.1 W maximum at rated load, which matters for enclosure thermal rise calculations if you're stacking multiple breakers in a sealed cabinet.