What this 200 A MCCB carries — and what it means for the panel
The Siemens 3VA1220-4GF42-0JH0 is a SENTRON molded case circuit breaker rated 200 A continuous at 40 °C, with four poles and a line-protection trip curve. The interrupting capacity hits 121 kA at 240 V and still delivers 75.6 kA at 415 V — enough to handle high-fault utility feeds without cascading upstream. At 690 V it still breaks 11.9 kA, so it holds up on 480Y/277 V or 600 V industrial services. Thermal derating starts at 55 °C: 194 A at 55 °C, 188 A at 60 °C, 182 A at 65 °C, 176 A at 70 °C. If the panel ambient runs hot, size the load side accordingly. This is a line-protection breaker — no ground-fault module, no communication function. It ships with a shunt trip (STL) for remote opening and comes pre-configured with two auxiliary switches plus one trip alarm switch (HQ). The auxiliary release is factory-fitted, so you don't need to open the cover to add one in the field. Insulation voltage rated 800 V, so it's comfortable on 480 V or 600 V class systems. Dimensions: 140 mm wide, 158 mm tall, 70 mm deep. Four-pole frame takes up about 5.5 inches of DIN-rail width — plan the gland plate and wireway fill before you lay out the panel. Power loss at full load is 42 W; that's not trivial in a sealed enclosure, so factor it into the thermal budget.