What this MCCB carries and why it matters
The Siemens SENTRON 3VA1120-4EF32-0DH0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection. At 40 °C it carries a continuous 20 A — the same rating holds through 55 °C, then derates to 19 A at 60 °C and above. That thermal curve means it fits a 20 A feeder without oversizing for warm panel ambient up to 55 °C. Breaking capacity is 121 kA at 240 V, dropping to 75.6 kA at 415 V and 52.5 kA at 440 V — still well above typical 25–50 kA SCCR requirements for North American and European distribution panels. At 690 V it still interrupts 11.9 kA, covering most industrial motor branch circuits. Rated insulation voltage is 800 V.
Built-in auxiliary and undervoltage release
This variant ships with two auxiliary switches plus a trip alarm switch (HQ), and an integrated undervoltage release (UVR). The UVR trips the breaker when control voltage drops below a set threshold — standard for safety circuits that need to drop power on loss of control supply. No separate undervoltage module to buy and mount. Power loss at full load is 14.5 W — modest for a 20 A MCCB, so heat buildup in a crowded enclosure stays manageable.
Physical fit and panel integration
Dimensions: 130 mm high, 76.2 mm wide, 70 mm deep. The 76.2 mm width is a standard 3-pole MCCB footprint.