Breaking capacity and selectivity planning
The Siemens 3VA1120-4GD46-0AA0 is a 4-pole SENTRON molded case circuit breaker rated for 20 A continuous current with a TM210 thermal-magnetic release. Its interrupting capacity varies with system voltage: 121 kA at 240 V, 76 kA at 415 V, 53 kA at 440 V, and 11.9 kA at both 500 V and 690 V. For a site electrical engineer planning coordination, the 121 kA at 240 V gives substantial headroom for high-fault panels, but the drop to 11.9 kA at 500 V means the available fault current at that voltage must be verified against the breaker's rating before committing the BOM line.
Thermal derating and continuous current
The breaker holds its full 20 A rating from 40 °C through 55 °C ambient. At 60 °C and 65 °C it derates to 19 A, and at 70 °C it stays at 19 A. For a panel OEM wireman, this means no fill-factor derating penalty in a standard 40 °C enclosure, but if the panel ambient runs above 55 °C — say, adjacent to a drive cabinet — the continuous load must be capped at 19 A. The TM210 release is a fixed thermal-magnetic design with no electronic adjustment; the trip curve is set at the factory.
Physical fit and panel integration
Dimensions are 130 mm height, 101.6 mm width, 70 mm depth. The 4-pole width (101.6 mm) is standard for a 4-pole MCCB in this frame size; it occupies four 25 mm module positions on a DIN rail. Front IP40 protection is suitable for enclosed panel mounting — not for washdown or outdoor exposure. The N-conductor protection is rated at 100 %, meaning the neutral pole is fully rated and switches with the phase poles.