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.
DIN-rail footprint and panel fit
Width is 76.2 mm, depth 70 mm, height 130 mm. The 3-pole body snaps onto standard DIN rail; front IP40 protection means the breaker is suited for enclosed panel mounting where incidental tool contact is the main concern, not washdown. Two HP auxiliary switches are built in for status feedback to a PLC or indicator lamp — no separate aux block to order.
What the ratings mean for the buyer
The 20 A continuous rating at 40 °C is the operating current for sizing the feeder conductor and upstream protective device. 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). No undervoltage release, no shunt trip, no ground-fault monitoring, no communication module — this is a basic line-protection MCCB, not a multifunction power breaker.