What this MCCB is and what it does
The Siemens SENTRON 3VA1120-3GE46-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 20 A continuous, with a TM220 thermal-magnetic overcurrent release. It's built for line protection — meaning it sits upstream of a distribution board or a heavy load, clearing faults before they damage downstream wiring or equipment. The interrupting capacity is the headline here: 75.6 kA at 240 V AC, 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V. That's a high-fault-rated MCCB — it can be installed on panels with substantial available fault current without needing a current-limiting fuse upstream, which simplifies coordination and saves panel space. Rated insulation voltage is 800 V, so it's suited for 690 V systems with adequate margin. The 20 A rating holds steady from 40 °C up to 55 °C, then derates to 19 A at 60–70 °C — useful to know if the breaker sits near heat sources or in a warm enclosure.
Where it goes and how it mounts
Measures 70 mm deep, 101.6 mm wide, and 130 mm high. IP40 on the front. No undervoltage release, no shunt trip, no communication module, no ground-fault monitoring — this is a plain-vanilla thermal-magnetic breaker for straightforward overcurrent protection. If you need remote tripping or ground-fault detection, you'd add external accessories or step to a different 3VA variant.