What this MCCB delivers on the line
The Siemens SENTRON 3VA1220-6EF32-0KH0 is a 3-pole molded case circuit breaker rated for 200 A continuous at 40 °C, with a breaking capacity of 220 kA at 240 V AC — enough to handle high-fault utility feeds or transformer secondaries without cascading upstream. It is designed for line protection, meaning it guards cables and busbars against overload and short-circuit, not motor starting duty. The built-in shunt trip (STL) lets a remote signal or safety relay drop the breaker instantly, and the auxiliary switch pack (2 aux + 1 trip alarm) feeds status back to a PLC or annunciator panel. Rated insulation voltage is 800 V, so it can sit in a 480 V or 600 V panel with margin. The 42 W maximum power loss at full load matters for enclosure heat budgeting — a sealed stainless panel running multiple breakers needs that figure to size ventilation or air conditioning.
Thermal derating and real-world current
The breaker holds its full 200 A rating from 40 °C up to 50 °C. Above that it derates linearly: 194 A at 55 °C, 188 A at 60 °C, 182 A at 65 °C, and 176 A at 70 °C. If your panel ambient runs hot — say inside a non-ventilated enclosure near a furnace line — use the 60 °C or 65 °C column for sizing, not the 40 °C number. Breaking capacity also drops with voltage: 154 kA at 415 V, 75.6 kA at 440 V, 30 kA at 500 V, and 17 kA at 690 V. For a 480 V panel the relevant figure is the 440 V column (75.6 kA) — that is the fault current this breaker can safely interrupt without welding contacts or venting gas.
Panel fit and mounting
Dimensions are 105 mm wide, 158 mm high, 70 mm deep — a standard 3-pole MCCB footprint that fits most DIN-rail or panel-mount enclosures without re-drilling. The 70 mm depth leaves clearance for rear-connected busbars or a deadfront cover. The auxiliary switch design (2 aux + 1 trip alarm HQ) and the shunt trip release are factory-installed, not field-add-on kits. Verify the wiring diagram matches your control voltage before panel assembly — the shunt trip coil draw is not listed here, but typical STL coils pull about 0.5 A at 24 VDC during the trip pulse.