The Siemens SENTRON 3VM1120-3ED16-0AA2 is a 1-pole molded case circuit breaker (MCCB) rated for 20 A continuous current, with a TM210 thermal-magnetic release. It's built for line protection — think feeder circuits in distribution panels where you need a compact, single-pole MCCB that coordinates with downstream breakers. The interrupting capacity is where this part earns its keep: 53 kA at 240 V AC and 8 kA at 415 V AC. That 53 kA figure at 240 V means it can handle high-fault scenarios common on the secondary side of a 240/120 V distribution transformer without needing a current-limiting fuse upstream. The 8 kA at 415 V is adequate for most European-style 400 V panelboards feeding motor control centers or lighting distribution.
Thermal derating and operating range
The 20 A rating holds steady from 40 °C all the way up to 55 °C — no derating needed in a warm panel. At 60 °C and above it steps down to 19 A. That's a clean, predictable curve: you can load it at 20 A in most standard enclosures without worrying about nuisance tripping from ambient heat. The operating temperature range is -25 °C to 70 °C, with storage from -40 °C to 80 °C.
Physical fit and panel integration
At 25.4 mm wide (1 inch exactly), this single-pole MCCB fits a standard 25 mm DIN-rail slot — one module width. Depth is 70 mm, height 130 mm. That's compact enough for a 12-way distribution board where every millimeter of rail space counts. The front face carries an IP40 protection rating, so it's fine for indoor panel use but not for washdown environments. No trip indicator, no undervoltage release, no communication module, no motor drive option — this is a bare-bones line-protection MCCB. The TM210 release is thermal-magnetic, so it gives you inverse-time overload protection plus instantaneous short-circuit trip. Rated insulation voltage is 500 V, and the max DC operational voltage is 125 V, so it can also serve in some DC branch circuits.