SENTRON 3VA1120-5EF32-0KA0 — 20 A MCCB with Shunt Trip
The Siemens 3VA1120-5EF32-0KA0 is a SENTRON 3-pole molded case circuit breaker rated 20 A continuous at 40 °C ambient, with a TM240 thermal-magnetic overcurrent release. Its headline interrupting rating is 187 kA at 240 VAC — that means it can safely clear a fault up to that current without welding contacts or cascading failure upstream, critical for high-fault panels near large transformers or service entrances. The breaker carries a shunt trip release (STL) for remote emergency-off or undervoltage tripping, and the supplied basic switch is 3VA11205EF320AA0. Rated insulation voltage is 800 V, so it handles 480/600 V distribution without derating the insulation path.
Breaking Capacity by Voltage — Selectivity Planning
Breaking capacity drops from 187 kA at 240 V to 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 500/690 V. For a 480 V panel, the 75.6 kA figure governs SCCR coordination — verify your available fault current stays under that to maintain series rating with downstream breakers.
Thermal Derating and Power Loss
Rated 20 A from 40 °C through 55 °C ambient; at 60 °C it derates to 19 A, holding through 70 °C. Maximum power loss is 12 W — negligible for panel heat budget but worth noting if the breaker is packed tight in a sealed enclosure. Operating range is -25 °C to 70 °C; storage range -40 °C to 80 °C.