Line protection MCCB, 2-pole, 20 A
The Siemens 3VM1120-3ED22-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It is a 2-pole unit rated 20 A at 40 °C with a TM210 thermal-magnetic overcurrent release — meaning the thermal trip is fixed at 20 A and the magnetic short-circuit pickup is 10× the rated current (200 A). Breaking capacity is 76 kA at 240 V AC and 53 kA at 415 V AC, so it handles high-fault-current service entrances or sub-distribution boards without cascading upstream. The insulation voltage is rated 500 V, and the front face carries IP40 protection — suitable for enclosed panel mounting, not open washdown areas.
Dimensions and panel fit
The 3VM1120-3ED22-0AA0 measures 70 mm deep, 50.8 mm wide, and 130 mm tall. That 2-inch width means it occupies a single 2-pole space in a standard Siemens panelboard or MCC bucket. Depth of 70 mm (2.76 in) leaves clearance for wiring gutters in most 8-inch-deep enclosures.
Thermal derating and operating limits
The breaker holds 20 A continuously from 40 °C through 55 °C ambient. At 60 °C it derates to 19 A, and at 70 °C it still carries 19 A — minimal drop, so it works in warm cabinets without oversizing. Operating ambient range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss is 8 W per pole.