MCCB for high-fault panels
The Siemens SENTRON 3VA1220-6EF42-0CH0 is a 4-pole molded case circuit breaker rated 200 A continuously at 40 °C, sized for main feeder or large subfeed protection in distribution panels. Its 220 kA interrupting capacity at 240 V handles high available fault current at the service entrance — common where utility transformers sit close to the switchboard. The 4-pole construction covers three-phase-plus-neutral, so it's the right choice for TN-S or TN-C-S systems where the neutral needs overcurrent protection. Breaking capacity steps down with voltage: 154 kA at 415 V, 75.6 kA at 440 V, 30 kA at 500 V, and 17 kA at 690 V. That SCCR curve means the same frame supports 480 V delta or 600 V wye installations, but the available fault current at the higher voltage must stay under the 30 kA or 17 kA ceiling respectively. For a 480 V panel with 65 kA available, this breaker fits only if the line side is impedance-limited or current-limited by an upstream device. Rated insulation voltage is 800 V, so the breaker is electrically rated for 690 V systems without derating the insulation path. The 44.5 W maximum power loss at full load matters for enclosure thermal rise — in a sealed NEMA 12 panel, that heat adds to the internal ambient and may require derating per the thermal curve above 40 °C.
Thermal derating and ambient range
The 3VA1220-6EF42-0CH0 holds full 200 A rating from 40 °C through 50 °C. Above that, current must be reduced: 194 A at 55 °C, 188 A at 60 °C, 182 A at 65 °C, and 176 A at 70 °C. In a hot switchroom or outdoor enclosure in direct sun, the 70 °C operating limit is the absolute ceiling — the breaker will still function but at 176 A continuous. Storage range is -40 °C to 80 °C, covering cold warehouse or hot container shipping without damage.
Built-in accessories and wiring
This variant ships with an undervoltage release (UVR) factory-installed — when control voltage drops, the breaker trips immediately, which is standard for emergency-stop or safety-shutdown circuits that need a loss-of-voltage trip. Auxiliary contacts include 2 auxiliary switches plus 1 trip alarm switch (HQ type), giving three separate signal paths for status feedback to a PLC or annunciator panel. The base switch mechanism is order code 3VA12206EF420AA0, meaning the trip unit, frame, and internal parts are a matched assembly — not a field-upgrade kit. Dimensions are 158 mm high, 140 mm wide, 70 mm deep. The 140 mm width is the standard 4-pole SENTRON 3VA12 frame footprint — it occupies four 35 mm DIN-rail modules (each 17.5 mm plus spacing). Panel cutout and busbar spacing must accommodate the 158 mm height; verify clearance above for arc-chamber venting per Siemens installation instructions.