Line protection MCCB, 20 A frame
The Siemens SENTRON 3VA1120-3EF36-0AB0 is a 3-pole molded case circuit breaker rated for line protection, carrying a continuous current Iu of 20 A at 40 °C and holding that rating through 50 °C before it begins to derate — 19.2 A at 55 °C, 18.8 A at 60 °C, 18.4 A at 65 °C, and 18 A at 70 °C. The TM240 thermal-magnetic release handles the overcurrent trip curve, with a maximum adjustable time delay tr of 1 s. Interrupting capacity runs 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V — numbers that govern the available fault current the breaker can safely clear without upstream coordination issues.
Width is 76.2 mm, depth 70 mm, height 130 mm.
The interrupting ratings at different voltages tell you the maximum fault current the breaker can interrupt at that system voltage — 75.6 kA at 240 V covers high-fault panels near large transformers; the 10.5 kA at 690 V still handles most industrial 690 V distribution. The TM240 release is thermal-magnetic, so it provides inverse-time overload protection (thermal element) plus instantaneous short-circuit trip (magnetic element).