The Siemens SENTRON 3VA1120-3EF32-0CH0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current of 20 A across the 40-55 °C ambient range and derating to 19 A at 60-70 °C. Its interrupting capacity at 240 V hits 75.6 kA, which gives solid headroom for high-fault panelboards where a standard MCB would weld shut. The breaker ships with an integrated undervoltage release (UVR) and a 2-auxiliary + 1 trip-alarm switch stack, so it's ready for shunt-trip and status feedback wiring without an add-on module.
Breaking capacity and selectivity
The 75.6 kA at 240 V is the headline number for North American panel schedules, but the IEC side matters too: 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at 500/690 V. That 690 V figure is unusual for a 20 A frame — most MCCBs in this current class top out around 25 kA at 690 V. The insulation voltage is rated at 800 V, so the breaker is electrically comfortable in 690 V IT systems or 480 V delta corners where phase-to-phase stress is higher than line-to-neutral.
Panel integration
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep — a standard 3-pole MCCB footprint for DIN-rail or screw-mount panel installation. The 2-aux + 1 trip-alarm switch configuration is factory-fitted, saving a slot on the DIN rail versus a separate aux block. Maximum power loss is 14.5 W, so thermal dissipation inside a sealed enclosure needs a quick check on the heat budget.
Environmental limits
Operating temperature range is -25 °C to 70 °C, with storage from -40 °C to 80 °C. The trip indicator is present, and the breaker includes an undervoltage release — no communication function, no ground-fault monitoring on this variant.