What this MCCB carries
The Siemens 3VA1120-5GD46-0AA0 is a 4-pole SENTRON molded case circuit breaker rated 20 A continuous with a TM210 thermal-magnetic overcurrent release. The 187 kA interrupting rating at 240 V AC means it clears high-fault bolted shorts without cascading upstream — sized for the main feeder or a high-capacity subfeed in a distribution panel. Breaking capacity drops to 121 kA at 415 V and 75.6 kA at 440 V, then to 17 kA at 500 V and 690 V — the same 17 kA figure at both voltages, which is unusual and worth noting if your system runs at 480/277 V or 600 V. At 690 V the 17 kA rating still covers most industrial motor branch circuits.
Thermal derating and panel fit
The breaker holds its full 20 A rating from 40 °C through 55 °C ambient. At 60 °C it derates to 19 A, and stays at 19 A through 70 °C. That flat derating curve simplifies panel layout — no need to oversize the frame for a warm enclosure. Dimensions are 70 mm deep, 101.6 mm wide, and 130 mm tall. The 4-pole width (about 4 inches) fits standard Siemens SENTRON mounting feet. Front IP40 protection is fine for a clean indoor panel; no washdown rating here.