What the ratings mean for fit
The Siemens SENTRON 3VA1120-5EF32-0DC0 is a 3-pole molded case circuit breaker (MCCB) rated 20 A continuous at up to 55 °C ambient — above that it derates to 19 A at 70 °C, so if your panel runs hot, size for the lower figure. Its breaking capacity hits 187 kA at 240 V AC and still delivers 121 kA at 415 V, meaning it can clear high-fault currents on an industrial distribution bus without cascading upstream. The insulation voltage is rated 800 V, so it's comfortable on 480/600 V systems. It's designed for line protection — not motor protection — and ships with an undervoltage release (UVR) built in, which is a common requirement for safety circuits that drop the breaker if control power is lost.
Dimensions and panel integration
At 130 mm high, 76.2 mm wide, and 70 mm deep, this MCCB fits a standard 3-pole breaker slot in a SENTRON distribution panel or any DIN-rail enclosure. The 70 mm depth means it clears most gland plates and back-panel wiring troughs without interference. Two auxiliary switches (HQ design) are included for status feedback to a PLC or remote indicator.