The Siemens 3VA1120-5EF36-0KA0 is a SENTRON molded case circuit breaker rated for 20 A continuous current across three poles, with a TM240 thermal-magnetic overcurrent release. It carries a 187 kA breaking capacity at 240 V AC, tapering to 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V — so the interrupting rating is highest at the lower distribution voltages common in North American panels, while still handling substantial fault currents at European 400 V-class supplies.
Thermal derating and panel fit
The breaker holds its full 20 A rating up to 50 °C ambient; above that it derates linearly to 18 A at 70 °C. That means a panel running at 55 °C knocks 0.8 A off the continuous rating — not a deal-breaker for most motor feeders, but worth checking if the enclosure sits near a heat source. The 130 mm height, 76.2 mm width, and 70 mm depth fit the standard SENTRON 3VA mounting footprint, so it drops into existing DIN-rail or screw-panel cutouts without re-drilling.