What it is and what it does
The Siemens SENTRON 3VA1020-3ED32-0CH0 is a 3-pole molded case circuit breaker (MCCB) rated for 20 A continuous current across its full ambient temperature range from 40 °C to 55 °C, derating only to 19 A at 60 °C through 70 °C. Its breaking capacity runs 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 7.5 kA at both 500 V and 690 V — so it handles high-fault industrial mains without cascading upstream. This breaker is designed for line protection, not motor or feeder protection, meaning it guards cables and busbars against overload and short circuit in distribution panels.
Built-in auxiliaries and releases
It ships with an undervoltage release (UVR) and two auxiliary switches plus one trip alarm switch (HQ), so you can wire remote status and undervoltage tripping without adding external modules. Rated insulation voltage is 800 V, and maximum power loss at rated current is 14.5 W — useful for thermal budgeting inside a sealed enclosure.
Panel fit and environment
At 70 mm deep, 76.2 mm wide, and 130 mm tall, this MCCB fits standard SENTRON 3VA panel footprints and mounts on a DIN rail or directly to a backplate. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The 14.5 W heat dissipation means you should allow natural convection clearance in the enclosure.