What this MCCB carries
The Siemens SENTRON 3VA1120-3EF36-0AA0 is a 3-pole molded case circuit breaker rated for 20 A continuous current, using a TM240 thermal-magnetic release. It's built for line protection in distribution panels — the TM240 release gives you a fixed thermal trip curve with magnetic pickup adjustable up to 320 A, so it handles motor inrush without nuisance tripping on moderate overloads. Interrupting capacity runs 75.6 kA at 240 V, 52.5 kA at 415 V, and 32 kA at 440 V — drops to 11.9 kA at 500 V and 690 V. That spread covers most low-voltage commercial and industrial service entrances, but at the higher voltages you're limited to lower-fault panels or downstream subfeeds. Rated insulation voltage is 800 V, and the max rated operational DC voltage is 500 V. On the front, protection is IP40 — fine for a closed panel, but not for washdown areas.
Mounting and thermal budget
Footprint is 76.2 mm wide, 130 mm tall, 70 mm deep — standard 3-pole MCCB spacing for DIN-rail or screw-mount panels. At full load it dissipates 12 W max, so in a sealed enclosure with other breakers you'll want to check the cumulative heat against your cabinet's derating curve. The continuous rating holds at 20 A from 40 °C up to 55 °C, then steps to 19 A at 60 °C through 70 °C. That's a clean thermal profile — no surprise derating until you're past 55 °C ambient.
Operating range and storage
Runs from -25 °C to 70 °C ambient; storage range is -40 °C to 80 °C. The storage minimum is the cold-soak limit for warehousing — the breaker won't be damaged sitting in an unheated warehouse, but don't energize it below -25 °C.