What this MCCB does and how it fits
The Siemens 3VA1120-6EF36-0CC0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection — the go-to for feeder circuits in distribution panels where you need high fault clearance without blowing the main. Three-pole, rated 20 A continuously at 40 °C (derates to 19 A at 70 °C), and carries a 220 kA interrupting rating at 240 V, stepping down to 154 kA at 415 V, 121 kA at 440 V, and 17 kA at 500/690 V. That SCCR headroom means it can sit downstream of a transformer or a large bus without coordination headaches. Rated insulation voltage is 800 V, so it's comfortable on 690 V line-to-line systems common in industrial drives and heavy machinery. Power dissipation maxes at 14.5 W — negligible for panel thermal budget, but worth noting if you're packing a dozen of these in a sealed enclosure. Operating temperature spans -25 °C to 70 °C; storage from -40 °C to 80 °C.
Built-in auxiliaries and releases
This variant ships with an undervoltage release (UVR) and two HQ auxiliary switches — no trip indicator, no voltage-trigger function, no ground-fault monitoring. The UVR is wired into the control circuit; if the coil voltage drops, the breaker trips. That's standard for safety circuits where loss of control power must open the feeder. The two auxiliary switches give you status feedback — one for the panel PLC, one for a remote annunciator.