Siemens 3VA1120-6EF32-0AA0 — 20 A MCCB with 220 kA at 240 V
The Siemens SENTRON 3VA1120-6EF32-0AA0 is a 3-pole molded case circuit breaker rated for 20 A continuous (Iu) with a TM240 thermal-magnetic release. It's a line-protection device — no ground-fault monitoring, no communication module. The headline number is the interrupting capacity: 220 kA at 240 V, dropping to 154 kA at 415 V, 121 kA at 440 V, and 17 kA at 500 V and 690 V. That 220 kA at 240 V means it can safely clear a fault at that level without upstream devices needing to coordinate — useful for high-fault utility feeds or transformer secondaries where the available short-circuit current is high. Rated insulation voltage (Ui) is 800 V, and the maximum DC operating voltage is 500 V. The thermal derating curve is flat from 40 °C to 55 °C at 20 A, then steps down to 19 A at 60 °C through 70 °C — so in a warm panel you lose only 1 A. Power loss peaks at 12 W. The front face carries IP40 protection, meaning it's sealed against tools and small objects but not water — standard for a panel-mounted MCCB. The adjustable instantaneous pickup (li) maxes out at 320 A — that's 16x the continuous rating, giving you headroom for motor inrush or transformer magnetizing current without nuisance tripping. The TM240 release is a fixed thermal-magnetic type; no electronic adjustment for long-time or short-time delays. Optional motor drive is available for remote operation.
Mounting and panel fit
Dimensions are 130 mm high, 76.2 mm wide, 70 mm deep. It mounts on a DIN rail or can be screw-fixed to a backplate. The 3-pole footprint is standard for this class — the 76.2 mm width is three modular units (each 25.4 mm). Verify gland-plate clearance for the 70 mm depth, especially if you're adding the optional motor drive.